Integrated laser lighting and LIDAR system

ABSTRACT

The present disclosure provides a mobile machine including a laser diode based lighting system having an integrated package holding at least a gallium and nitrogen containing laser diode and a wavelength conversion member. The gallium and nitrogen containing laser diode is configured to emit a first laser beam with a first peak wavelength. The wavelength conversion member is configured to receive at least partially the first laser beam with the first peak wavelength to excite an emission with a second peak wavelength that is longer than the first peak wavelength and to generate the white light mixed with the second peak wavelength and the first peak wavelength. The mobile machine further includes a light detection and ranging (LIDAR) system configured to generate a second laser beam and manipulate the second laser beam to sense a spatial map of target objects in a remote distance.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.15/841,053, filed Dec. 13, 2017, the entire contents of which areincorporated herein by reference for all purposes.

BACKGROUND

In the late 1800's, Thomas Edison invented the light bulb. Theconventional light bulb, commonly called the “Edison bulb,” has beenused for over one hundred years for a variety of applications includinglighting and displays. The conventional light bulb uses a tungstenfilament enclosed in a glass bulb sealed in a base, which is screwedinto a socket. The socket is coupled to an AC power or DC power source.The conventional light bulb can be found commonly in houses, buildings,and outdoor lightings, and other areas requiring light or displays.Unfortunately, drawbacks exist with the conventional light bulb:

-   -   The conventional light bulb dissipates more than 90% of the        energy used as thermal energy.    -   The conventional light bulb routinely fails due to thermal        expansion and contraction of the filament element.    -   The conventional light bulb emits light over a broad spectrum,        much of which is not perceived by the human eye.    -   The conventional light bulb emits in all directions, which is        undesirable for applications requiring strong directionality or        focus, e.g. projection displays, optical data storage, etc.

To overcome some of the drawbacks of the conventional light bulb,several alternatives have been developed including fluorescent lamps,Mercury vapor lamps, sodium vapor lamps, other high-intensity discharge(HID) lamps, gas discharge lamps such as neon lamps, among others. Theselamp technologies in general suffer from similar problems to Edisonlamps as well as having their own unique drawbacks. For example,fluorescent lamps require high voltages to start, which can be in therange of a thousand volts for large lamps, and also emit highlynon-ideal spectra that are dominated by spectral lines.

In the past decade, solid state lighting has risen in importance due toseveral key advantages it has over conventional lighting technology.Solid state lighting is lighting derived from semiconductor devices suchas diodes which are designed and optimized to emit photons. Due to thehigh efficiency, long lifetimes, low cost, and non-toxicity offered bysolid state lighting technology, light emitting diodes (LED) haverapidly emerged as the illumination technology of choice. An LED is atwo-lead semiconductor light source typically based on a p-i-n junctiondiode, which emits electromagnetic radiation when activated. Theemission from an LED is spontaneous and is typically in a Lambertianpattern. When a suitable voltage is applied to the leads, electrons andholes recombine within the device releasing energy in the form ofphotons. This effect is called electroluminescence, and the color of thelight is determined by the energy band gap of the semiconductor.

Appealing as practical electronic components in 1962 the earliest LEDsemitted low-intensity infrared light. Infrared LEDs are still frequentlyused as transmitting elements in remote-control circuits, such as thosein remote controls for a wide variety of consumer electronics. The firstvisible-light LEDs were also of low intensity, and limited to red.Modern LEDs are available across the visible, ultraviolet, and infraredwavelengths, with very high brightness.

The earliest blue and violet gallium nitride (GaN)-based LEDs werefabricated using a metal-insulator-semiconductor structure due to a lackof p-type GaN. The first p-n junction GaN LED was demonstrated by Amanoet al. using the LEEBI treatment to obtain p-type GaN in 1989. Theyobtained the current-voltage (I-V) curve and electroluminescence of theLEDs, but did not record the output power or the efficiency of the LEDs.Nakamura et al. demonstrated the p-n junction GaN LED using thelow-temperature GaN buffer and the LEEBI treatment in 1991 with anoutput power of 42 μW at 20 mA. The first p-GaN/n-InGaN/n-GaN DH blueLEDs were demonstrated by Nakamura et al. in 1993. The LED showed astrong band-edge emission of InGaN in a blue wavelength regime with anemission wavelength of 440 nm under a forward biased condition. Theoutput power and the EQE were 125 μW and 0.22%, respectively, at aforward current of 20 mA. In 1994, Nakamura et al. demonstratedcommercially available blue LEDs with an output power of 1.5 mW, an EQEof 2.7%, and the emission wavelength of 450 nm. On Oct. 7, 2014, theNobel Prize in Physics was awarded to Isamu Akasaki, Hiroshi Amano andShuji Nakamura for “the invention of efficient blue light-emittingdiodes which has enabled bright and energy-saving white light sources”or, less formally, LED lamps.

By combining GaN-based LEDs with wavelength converting materials such asphosphors, solid-state white light sources were realized. Thistechnology utilizing GaN-based LEDs and phosphor materials to producewhite light is now illuminating the world around us as a result of themany advantages over incandescent light sources including lower energyconsumption, longer lifetime, improved physical robustness, smallersize, and faster switching. LEDs are now used in applications as diverseas aviation lighting, automotive headlamps, advertising, generallighting, traffic signals, and camera flashes. LEDs have allowed newtext, video displays, and sensors to be developed, while their highswitching rates can be very useful in communications technology. LEDs,however, are not the only solid-state light source and may not bepreferable light sources for certain lighting applications. Alternativesolid state light sources utilizing stimulated emission, such as laserdiodes (LDs) or super-luminescent light emitting diodes (SLEDs), providemany unique features advantageously over LEDs.

In 1960, the laser was demonstrated by Theodore H. Maiman at HughesResearch Laboratories in Malibu. This laser utilized a solid-state flashlamp-pumped synthetic ruby crystal to produce red laser light at 694 nm.Early visible laser technology comprised lamp pumped infrared solidstate lasers with the output wavelength converted to the visible usingspecialty crystals with nonlinear optical properties. For example, agreen lamp pumped solid state laser had 3 stages: electricity powerslamp, lamp excites gain crystal which lases at 1064 nm, 1064 nm goesinto frequency conversion crystal which converts to visible 532 nm. Theresulting green and blue lasers were called “lamped pumped solid statelasers with second harmonic generation” (LPSS with SHG) had wall plugefficiency of ˜1%, and were more efficient than Ar-ion gas lasers, butwere still too inefficient, large, expensive, fragile for broaddeployment outside of specialty scientific and medical applications. Toimprove the efficiency of these visible lasers, high power diode (orsemiconductor) lasers were utilized. These “diode pumped solid statelasers with SHG” (DPSS with SHG) had 3 stages: electricity powers 808 nmdiode laser, 808 nm excites gain crystal, which lases at 1064 nm, 1064nm goes into frequency conversion crystal which converts to visible 532nm. As high power laser diodes evolved and new specialty SHG crystalswere developed, it became possible to directly convert the output of theinfrared diode laser to produce blue and green laser light output. These“directly doubled diode lasers” or SHG diode lasers had 2 stages:electricity powers 1064 nm semiconductor laser, 1064 nm goes intofrequency conversion crystal which converts to visible 532 nm greenlight. These lasers designs are meant to improve the efficiency, costand size compared to DPSS-SHG lasers, but the specialty diodes andcrystals required make this challenging today.

Solid-state laser light sources, due to the narrowness of their spectrawhich enables efficient spectral filtering, high modulation rates, andshort carrier lifetimes, smaller in size, and far greater surfacebrightness compared to LEDs, can be more preferable as visible lightsources as a means of transmitting information with high bandwidth inmany applications including lighting fixtures, lighting systems,displays, projectors and the like. Advancements of new GaN-based bluelaser technology based on improved processes have substantially reducedmanufacture cost and opened opportunities for utilizing the modulatedlaser signal and the light spot directly to measure and or interact withthe surrounding environment, transmit data to other electronic systems,and respond dynamically to inputs from various sensors. Suchapplications are herein referred to as “smart lighting” applications tobe disclosed throughout the specification herein.

Originating in the 1960s shortly after the invention of the laser, lightdetection and ranging (LIDAR) technology emerged as a promising methodto spatially map and survey an environment and has more recently becomea critical technology for the 21^(st) century. LIDAR leverages the highbrightness, directionality, and in some applications the coherence oflasers to measure distance to a target object by illuminating thattarget object or environment with a pulsed laser light signal andmeasurement of the reflected pulse signal with a sensor. Differences inlaser return times [time of flight] and/or wavelengths or phase can thenbe used to make digital three dimensional-representations of the targetobject or environment.

Employing infrared laser wavelengths, LIDAR is conventionally used tomake high-resolution maps, with applications in geodesy, geomatics,archaeology, geography, geology, geomorphology, seismology, forestry,atmospheric physics, laser guidance, airborne laser swath mapping(ALSM), and laser altimetry. The technology is also used for control andnavigation for some autonomous cars. Lidar sometimes is called laserscanning and 3D scanning, with terrestrial, airborne, and mobileapplications.

SUMMARY

The present invention provides system, apparatus configured with varioussensor-based feedback loops integrated with gallium and nitrogencontaining laser diodes based on a transferred gallium and nitrogencontaining material laser process and methods of manufacture and usethereof. Merely by examples, the invention provides remote andintegrated smart laser lighting devices and methods, projection displayand spatially dynamic lighting devices and methods, LIDAR, LiFi, andvisible light communication devices and methods, and variouscombinations of above in applications of general lighting, commerciallighting and display, automotive lighting and communication, defense andsecurity, industrial processing, and internet communications, andothers.

This invention describes novel LIDAR technologies including gallium andnitrogen containing laser diodes and laser based lighting systems. In afirst set of embodiments described in in the present invention thegallium and nitrogen containing laser diodes provide improvedfunctionality, size, cost, sensitivity, or other advantages to LIDARsystems by way of adding one or more visible laser sources to thesystem. Additionally, in some embodiments of the present invention LIDARtechnology is combined with smart lighting technology including laserbased lighting systems. Specific embodiments of this invention employ atransferred gallium and nitrogen containing material process forfabricating laser diodes or other gallium and nitrogen containingdevices (as shown in U.S. Pat. Nos. 9,666,677 and 9,379,525, filed byone of inventors of this application) enabling benefits overconventional fabrication technologies.

In an additional group of smart laser lighting embodiments, thisinvention can include novel uses and configurations of gallium andnitrogen containing laser diodes in communication systems such asvisible light communication systems such as Li-Fi systems,communications using the convergence of lighting and display with staticor dynamic spatial patterning using beam shaping elements such as MEMSscanning mirrors, and communications triggered by integrated sensorfeedback. The smart laser lighting can be combined with LIDAR technologyfor enhanced system functionality and/or enhanced LIDAR function.Specific embodiments of this invention employ a transferred gallium andnitrogen containing material process (U.S. Pat. Nos. 9,666,677 and9,379,525) for fabricating laser diodes or other gallium and nitrogencontaining devices enabling benefits over conventional fabricationtechnologies.

In a different group of smart laser based lighting embodiments, thepresent invention provides gallium and nitrogen based lasers lightsources configured for one or more predetermined light characteristicresponses such as a light movement response, a light color response, alight brightness response, or other responses. The smart laser lightingcan be combined with LIDAR technology for enhanced system functionalityand/or enhanced LIDAR function. Specific embodiments of this inventionemploy a transferred gallium and nitrogen containing material process(U.S. Pat. Nos. 9,666,677 and 9,379,525) for fabricating laser diodes orother gallium and nitrogen containing devices enabling benefits overconventional fabrication technologies.

In yet another group of smart laser based lighting embodiments, thepresent invention provides gallium and nitrogen based lasers lightsources coupled to one or more sensors with a feedback loop or controlcircuitry to trigger the light source to react with one or morepredetermined responses such as a communication response with a VLCsignal or dynamic spatial patterning of light, a light movementresponse, a light color response, a light brightness response, a spatiallight pattern response, other response, or a combination of responses.The smart laser lighting can be combined with LIDAR technology forenhanced system functionality and/or enhanced LIDAR function. Specificembodiments of this invention employ a transferred gallium and nitrogencontaining material process for fabricating laser diodes or othergallium and nitrogen containing devices enabling benefits overconventional fabrication technologies.

In an aspect, the present invention provides a mobile machine includinga laser diode based lighting system having an integrated package holdingat least a gallium and nitrogen containing laser diode and a wavelengthconversion member, the gallium and nitrogen containing laser diodeconfigured to emit a first laser beam with a first peak wavelength. Thewavelength conversion member is configured to receive at least partiallythe first laser beam with the first peak wavelength to excite anemission with a second peak wavelength that is longer than the firstpeak wavelength and to generate the white light mixed with the secondpeak wavelength and the first peak wavelength. The mobile machinefurther includes a light detection and ranging (LIDAR) system configuredto generate a second laser beam and manipulate the second laser beam tosense a spatial map of target objects in a remote distance.

Optionally, the white light is configured as an illumination source forilluminating the target objects and their surrounding environmentdynamically moved as the mobile machine.

Optionally, the gallium and nitrogen containing laser diode isconfigured to produce the first laser beam with the first peakwavelength in a blue color range. The wavelength conversion memberincludes a phosphor material configured to be excited by the first laserbeam in the blue color range to produce the second peak wavelength in abroad color range including yellow color.

Optionally, the gallium and nitrogen containing laser diode isconfigured to produce the first laser beam with the first peakwavelength in a violet color range. The wavelength conversion memberincludes a phosphor material configured to be excited by the first laserbeam in the violet color range to produce the second peak wavelength ina broad color range including green color.

Optionally, the phosphor material is comprised of a ceramic yttriumaluminum garnet (YAG) doped with Ce or a single crystal YAG doped withCe or a powdered YAG comprising a binder material. The the phosphor hasan optical conversion efficiency of greater than 50 lumen per opticalwatt, greater than 100 lumen per optical watt, greater than 200 lumenper optical watt, or greater than 300 lumen per optical watt.

Optionally, the phosphor material is configured to operate in a modeselected from a reflective mode, a transmissive mode, and a combinationof a reflective mode and a transmissive mode in association withreceiving the first laser beam with the first peak wavelength to excitethe emission with the second peak wavelength.

Optionally, the integrated package includes the wavelength conversionmember configured as a remote pumped phosphor and a space supportingfree-space-optics to guide the laser beam from the gallium and nitrogencontaining laser diode to the remote pumped phosphor.

Optionally, the integrated package includes the wavelength conversionmember configured as a remote pumped phosphor and an optical fiber toguide the laser beam from the gallium and nitrogen containing laserdiode to the remote pumped phosphor.

Optionally, the integrated package includes a surface mount device (SMD)package including a common support member configured to support at leastone gallium and nitrogen containing laser diode and the wavelengthconversion member.

Optionally, the at least one gallium and nitrogen containing laser diodeincludes multiple laser diodes such as 2 laser diodes, 3 laser diodes,or 4 laser diodes to generate 2 laser beams, 3 laser beams, or 4 laserbeams, respectively. The multiple laser beams form an excitation spot onthe wavelength conversion member.

Optionally, each of the multiple laser diodes is characterized by one ofmultiple first peak wavelengths in 420 nm to 485 nm blue color range.The multiple first peak wavelengths result in an improved color qualityof the white light.

Optionally, the wavelength conversion member includes a first phosphormaterial configured to be excited by the first laser beam with the firstpeak wavelength to produce a first emission of a second peak wavelengthand a second phosphor material configured to be excited by the laserbeam to produce a second emission with a third peak wavelength.

Optionally, the gallium and nitrogen containing laser diode ischaracterized by the first laser beam with the first peak wavelength inviolet color range. The first phosphor material is characterized by thefirst emission with the second peak wavelength in blue color range. Thesecond phosphor material is characterized by the second emission withthe third wavelength in yellow color range. The white light is comprisedof at least the first emission and the second emission.

Optionally, the LIDAR system includes a laser subsystem including adriver and a laser diode to generate the second laser beam and atransmitter to transmit one or more sensing light signals based on thesecond laser beam out to environment. Additionally, the LIDAR systemincludes a detection subsystem including at least a receiver to detectreflected light signals from the environment based on the one or moresensing light signals. Furthermore, the LIDAR system includes a signalprocessor to synchronize the transmitter and the receiver to computerespective time of flight for the one or more sensing light signals andthe reflected light signals to generate a spatial map image and identifyobjects or areas of interest.

Optionally, the one or more sensing light signals are based on thesecond laser beam at a wavelength selected from about 905 nm, about 1000nm, about 1064 nm, or about 1550 nm, or about 532 nm.

Optionally, the LIDAR system includes a scanning MEMS or other beamscanner for manipulating the second laser beam carrying the one or moresensing light signals projected with a survey pattern to theenvironment.

Optionally, the LIDAR system is configured with a detector array forsimultaneous detection of the reflected light signals at multiplelocations in a plane for generating some or all pixels of a frame ofimage.

Optionally, the mobile machine further is configured as a vehicleincluding autonomous vehicle, aircraft, spacecraft, drone, motorcycle,boat, marine vehicle, submarine, bicycle, tricycle, electrical scooter.

Optionally, the mobile machine further includes a signal processor thatis configured to control the laser diode based lighting system based onfeedback information provided from the LIDAR system. The laser diodebased lighting system is configured to preferentially use the whitelight to illuminate at least one of the target objects and surroundingareas identified by the LIDAR system.

Optionally, the laser diode based lighting system is controlled todynamically change illumination intensity, illumination pattern, beamangle, beam shape, and beam location of the white light based on atleast some feedback information from the LIDAR system when detecting atleast one moving target object.

Optionally, the feedback information includes mapping image of the atleast one oncoming moving object obtained by the LIDAR system and thewhite light is used for send out messages through a visible lightcommunication network.

In another aspect, the present disclosure provides a LIDAR system. TheLIDAR system includes a power source and a processor coupled to thepower source and configured to supply power and generate a drivingcurrent and a control signal. The LIDAR system further includes agallium and nitrogen containing laser diode configured to be driven bythe driving current to emit a first light with a first peak wavelengthand a beam splitter splitting the first light to a first portion and asecond portion. Additionally, the LIDAR system includes a wavelengthconversion member configured to receive the first portion of the firstlight with the first peak wavelength to generate a second light with asecond peak wavelength that is longer than the first peak wavelength.The first light is combined with the second light to produce a whitelight. The LIDAR system further includes a beam shaping element to shapethe white light as an illumination source. Furthermore, the LIDAR systemincludes a beam projector configured to receive the second portion ofthe first light driven by power source and the control signal from theprocessor to form a sensing light signal and transmit the sensing lightsignal to a remote target object including its surroundings. Moreover,the LIDAR system includes a detector configured to detect reflectedlight signals of the sensing light signal from the remote target object,thereby deducing a substantial 3D information of the target object basedon the reflected light signals.

Optionally, the gallium and nitrogen containing laser diode yields thefirst light as a blue laser light with first peak wavelength ranging inabout 420 nm to about 485 nm.

Optionally, the LIDAR system further includes a beam steering elementconfigured to process a beam of the white light to create a spatiallydynamic illumination for the remote target object.

Optionally, the sensing light signal includes some light pulses incertain modulation scheme determined by the control signal from theprocessor.

Optionally, the beam projector includes a MEMS controlled scannerconfigured to dynamically scan a beam of the sensing light signal acrossthe remote target object.

Optionally, the beam projector includes a microdisplay module fordigitally processing a plurality of pixels of the sensing light signalfor sensing the remote target object.

Optionally, the detector includes at least one selected from aphotodiode, a photoresistor, a CCD camera, an antenna, a scanning mirroror a microdisplay coupled to a photodiode to convert the reflected lightsignals to electrical signals.

Optionally, the detector includes a detector array for simultaneouslydetecting reflected light signals at different locations across a singleplane.

Optionally, the LIDAR system further includes a receiver coupled to thedetector. The receiver includes a signal processor to convert theelectrical signals detected by the detector to digital signals and aTime-of-Flight detection module configured to perform Time-of-Flightcalculations based on the digital signals.

Optionally, the blue laser light is characterized by high power levelsin one range selected from 1 mW to 10 mW, 10 mW to 100 mW, 100 mW to 1W, and 1 W to 10 W capable of sensing and mapping the remote targetobject under damp condition with relative humidity level in each offollowing ranges of greater than 25%, greater than 50%, greater than75%, and greater than 100%.

In yet another aspect, the present disclosure provides a LIDAR systemincluding a power source, a processor coupled to the power source andconfigured to supply power and generate a driving current, and a galliumand nitrogen containing laser diode configured to be driven by thedriving current to emit a first light with a first peak wavelength.Additionally, the LIDAR system includes a wavelength conversion memberconfigured to receive at least partially the first light to reemit asecond light with a second peak wavelength that is longer than the firstpeak wavelength and to combine a portion of the first light with thesecond light to produce a white light. The LIDAR system further includesa beam shaper coupled to the wavelength conversion member to receive thewhite light to generate an illumination source further comprising afirst sensing light signal based on the first peak wavelength and asecond sensing light signal based on the second peak wavelength.Furthermore, the LIDAR system includes at least a first beam projectorcoupled to the beam shaper and configured to direct at least partiallythe white light to illuminate one or more target objects and to transmitrespectively the first sensing light signal and the second sensing lightsignal for mapping a remote area including the one or more targetobjects and their surroundings. Moreover, the LIDAR system includes adetector configured to detect reflected signals of the first sensinglight signal to generate a first image of the one or more target objectsand detect some additional reflected signals of the second sensing lightsignal to generate a second image of the one or more target objects.

Optionally, the gallium and nitrogen containing laser diode isconfigured to generate the first light with the first peak wavelength inviolet or blue color range and the wavelength conversion member includesa yellow phosphor configured to generate the second light with thesecond peak wavelength in yellow color range.

Optionally, the LIDAR system further includes a collimator configured tofocus the first light with a first peak wavelength to the wavelengthconversion member within a spot size of 50 μm to 1 mm.

Optionally, the LIDAR system further includes a second beam projectorcoupled to the beam shaper and configured to direct at least partiallythe white light for illuminating the one or more target objects.

Optionally, the beam shaper includes one or more optical elements tosplit the white light partially collimated to a first beam of anilluminate light signal with a combination of the first peak wavelengthand the second peak wavelength and partially collimated to a second beamof the first sensing light signal centered with the first peakwavelength and a third beam of the second sensing light signal centeredwith the second peak wavelength.

Optionally, the beam projector includes one or more transmittercomponents to transmit the first sensing light signal centered with thefirst peak wavelength and the second sensing light signal centered withthe second peak wavelength in some pulses with a modulation scheme.

Optionally, the beam projector further includes one or more opticalelements for directing the second beam of the first sensing light signaland the third beam of the second sensing light signal to map the remotearea including one or more target objects and their surroundings.

Optionally, the one or more optical elements includes a first opticalsteering element selected from a MEMS controlled scanner, adigital-light processing (DLP) chip, and a liquid crystal on silicon(LCOS) chip for dynamically scanning the second beam and the third beamover the one or more target objects to respectively create a first 3Dmap characterized by the first peak wavelength and a second 3D mapcharacterized by the second peak wavelength.

Optionally, the one or more optical elements include a second opticalsteeling element for scanning the first beam of the illumination lightsignal to illuminate at least part of the one or more target objects.

Optionally, the beam projector includes a hybrid collimator configuredas a center beam collimator separated from an outer beam collimator. Thecenter beam collimator is configured to collimate a second beam of thefirst sensing light signal and a third beam of the second sensing lightsignal to less than 1 or 2 degrees for LIDAR sensing and the outer beamcollimator is configured to collimate a first beam of the illuminationlight signal to less than 15 degrees for LIDAR illumination.

Optionally, the processor includes a modulator configured to provide amodulation signal with a first rate to drive the gallium and nitrogencontaining laser diode to emit the first light with a first peakwavelength which is interrupted with a second rate. The second rate issubstantially synchronized with a delayed modulation rate of the secondlight of yellow color remitted from the wavelength conversion member.

Optionally, the detector includes a first signal receiver configured todetect reflected signals of the first sensing light signal to generate afirst image of the one or more target objects. The detector furtherincludes a second signal receiver configured to detect reflected signalsof the second sensing light signal to generate a second image of the oneor more target objects. The first image generated by the first signalreceiver is synchronized with the second image generated by the secondsignal receiver to obtain a color-differential image of the one or moretarget objects.

In still another aspect, the present disclosure provides another LIDARsystem. The LIDAR system includes a power source and a processor coupledto the power source and configured to supply power and generate drivingcurrents. The LIDAR system further includes a gallium and nitrogencontaining laser diode configured to be driven by a driving current fromthe processor to emit a first light with a first peak wavelength.Additionally, the LIDAR system includes a wavelength conversion memberconfigured to receive at least partially the first light to reemit asecond light with a second peak wavelength that is longer than the firstpeak wavelength and to combine a portion of the first light with thesecond light to produce a white light. The LDAR system further includesa beam shaper coupled to the wavelength conversion member to receive thewhite light to generate an illumination source further comprising asensing light signal based on one of the first peak wavelength and thesecond peak wavelength. Furthermore, the LIDAR system includes a beamprojector coupled to the beam shaper and configured to direct at leastpartially the white light to illuminate one or more target objects andto transmit the sensing light signal for mapping a remote area includingthe one or more target objects and their surroundings. Moreover, theLIDAR system includes a detector configured to detect reflected signalsof the sensing light signal to generate a first image of the one or moretarget objects and their surroundings.

Optionally, the gallium and nitrogen containing laser diode isconfigured to generate the first light with the first peak wavelength inviolet or blue color range and the wavelength conversion member includesa yellow phosphor configured to generate the second light with thesecond peak wavelength in yellow color range.

Optionally, the LIDAR system further includes a collimator configured tofocus the first light with a first peak wavelength to the wavelengthconversion member within a spot size of 50 μm to 1000 μm.

Optionally, the LIDAR system further includes a second beam projectorcoupled to the beam shaper and configured to direct at least partiallythe white light for illuminating the one or more target objects.

Optionally, the beam shaper includes one or more optical elements tosplit the white light partially for generating a first beam of anilluminate light signal with a combination of the first peak wavelengthand the second peak wavelength and partially for generating a secondbeam of the sensing light signal centered with one of the first peakwavelength and the second peak wavelength.

Optionally, the beam projector includes a transmitter component totransmit the sensing light signal centered with one of the first peakwavelength and the second peak wavelength in some modulated pulses.

Optionally, the beam projector further includes one or more opticalelements for directing the first beam of the illumination light signaland the second beam of the sensing light signal in some modulated pulsesto the remote area including the one or more target objects and theirsurroundings.

Optionally, the one or more optical elements includes a first opticalsteering element selected from a MEMS controlled scanner, adigital-light processing (DLP) chip, and a liquid crystal on silicon(LCOS) chip for dynamically scanning the second beam over the targetobjects to create a 3D map characterized by one of the first peakwavelength and the second wavelength.

Optionally, the one or more optical elements includes a second opticalsteering element for scanning the first beam of the illumination lightsignal to illuminate at least part of the one or more target objects.

Optionally, the beam projector includes a hybrid collimator configuredas a center beam collimator separated from an outer beam collimator. Thecenter beam collimator is configured to collimate the second beam of thesensing light signal to less than 1 or 2 degrees for LIDAR sensing andthe outer beam collimator is configured to collimate the first beam ofthe illumination light signal to less than 15 degrees for illumination.

Optionally, the processor includes a modulator configured to provide amodulation signal with a first rate to drive the gallium and nitrogencontaining laser diode to emit the first light with a first peakwavelength which is interrupted with a second rate. The second rate issubstantially synchronized with a delayed modulation rate of the secondlight of yellow color reemitted from the wavelength conversion member.

Optionally, the modulation signals are generated based on input datafrom an external source.

Optionally, the detector includes a first signal receiver configured todetect reflected signals of the sensing light signal to generate a firstimage of the one or more target objects and their surroundings.

Optionally, the LIDAR system further includes a second laser diodeconfigured to be driven by a driving current from the processor togenerate a third light with a third peak wavelength. The third lightbypasses the wavelength conversion member.

Optionally, the beam shaper is configured to receive the third lightwith the third peak wavelength and to generate a second sensing lightsignal.

Optionally, the beam projector further is configured to project a thirdbeam of the second sensing light signal to scan over the remote areaincluding the one or more target objects and their surroundings tocreate another 3D map characterized by the third peak wavelength.

Optionally, the detector includes a first signal receiver configured todetect reflected signals of the sensing light signal to generate a firstimage of the one or more target objects characterized by the one of thefirst peak wavelength and the second peak wavelength. The detectorfurther includes a second signal receiver configured to detect reflectedsignals of the second sensing light signal to generate a second image ofthe one or more target objects characterized by the third peakwavelength. The first image is synchronized with the second image toobtain a color-differential image of the one or more target objects.

In yet still another aspect, the present disclosure provides a LIDARsystem. The LIDAR system includes a power source, a processor coupled tothe power source and configured to supply power to a driver to generatea first driving current and a second driving current includingmodulation signals based on input data from an external source, and agallium and nitrogen containing laser diode configured to be driven bythe first driving current to emit a first light with a first peakwavelength. Additionally, the LIDAR system includes a sensing laserdiode configured to be driven by the second driving current to emit asecond light with a second peak wavelength configured to be a sensinglight signal. The LIDAR system further includes a wavelength conversionmember configured to receive at least partially the first light toreemit a third light with a third peak wavelength that is longer thanthe first peak wavelength. The third light is combined with at leastpartially the first light to yield a white light and configured to pass,scatter, or reflect the second light substantially without absorption.Furthermore, the LIDAR system includes one or more optical elementscoupled to the wavelength conversion member to receive the white lightand to collimate, steer, and project a first beam of the white light forilluminating one or more remote objects, and to receive the second lightto project a second beam of the sensing light signal centered with thesecond peak wavelength for mapping an area including the one or moreremote objects and their surroundings. Moreover, the LIDAR systemincludes a detector configured to detect reflected signals of thesensing light signal for mapping the one or more remote objects.

Optionally, the gallium and nitrogen containing laser diode isconfigured to generate the first light with the first peak wavelength inviolet or blue color range.

Optionally, the sensing laser diode includes an infrared laser diode foremitting the second light with the second peak wavelength in infraredrange selected from one of 905 nm, 1000 nm, 1064 nm, 1300 nm, or 1550nm.

Optionally, the wavelength conversion member includes a yellow phosphorconfigured to generate the third light with the third peak wavelength inyellow color range.

Optionally, the wavelength conversion member further includes a bluephosphor configured to receive the second light and let the second lightto pass substantially without absorption.

Optionally, the one or more optical elements includes a first collimatorconfigured to collimate the white light to the first beam to less than15 degrees and a steering element for scanning the first beam ofillumination with a first pattern over at least part of the one or moreremote objects.

Optionally, the one or more optical elements includes a secondcollimator to collimate the second light to the second beam of thesensing light signal to less than 1 or 2 degrees and includes aprojector configured to project the second beam of the sensing lightsignal with a second pattern to the one or more target objects and theirsurroundings. The second pattern is wider than the first pattern.

Optionally, the projector includes one optical device selected from aMEMS controlled scanner, a digital-light processing (DLP) chip, and aliquid crystal on silicon (LCOS) chip for generating a mapping patternwith a plurality of pixels and dynamically scanning over the one or moretarget objects to generate a 3D map thereof.

Optionally, the processor includes a first modulator configured toprovide a first modulation signal with a first rate to drive the galliumand nitrogen containing laser diode to emit the first light with thefirst peak wavelength which is interrupted with a second rate. Thesecond rate is substantially synchronized with a delayed modulation rateof the second light of yellow color reemitted from the wavelengthconversion member.

Optionally, the first modulator is configured to provide the firstmodulation signal based on input data from an external source foramplitude modulation of the first light with the first peak wavelengthin violet or blue range.

Optionally, the processor includes a second modulator configured toprovide a second modulation signal to drive the sensing laser diode toemit the second light with the second peak wavelength and drive atransmitter component to transmit the sensing light signal with pulsemodulation.

Optionally, the second modulator is configured to provide a secondmodulation signal based on feedback information from the detector basedon reflected signals from the one or more remote objects with optimalview angle and pattern for LIDAR sensing.

Optionally, the detector includes at least one selected from aphotodiode, a photoresistor, a CCD camera, an antenna, a scanning mirroror a microdisplay coupled to a photodiode to convert the reflected lightsignals to electrical signals. The electrical signal is time-dependent.

Optionally, the detector further includes a signal receiver configuredto convert the electrical signals to an image of the one or more targetobjects and their surroundings. The image is characterized substantiallyby the second peak wavelength and is time-dependent.

Alternatively, the present disclosure also provides an integrated LIDARsystem. The system includes a power source and a processor coupled tothe power source and configured to supply power to a driver to generatea first driving current and a second driving current includingmodulation signals based on input data from an external source.Additionally, the system includes a gallium and nitrogen containinglaser diode configured to be driven by the first driving current to emita first light with a first peak wavelength and a sensing laser diodeconfigured to be driven by the second driving current to emit a secondlight with a second peak wavelength. The system further includes awavelength conversion member configured to receive at least partiallythe first light to reemit a third light with a third peak wavelengththat is longer than the first peak wavelength, the third light combinedwith at least partially the first light yielding a white light. Thewavelength conversion member is also configured to pass, scatter, and/orreflect the second light substantially without absorption. Furthermore,the system includes a first set of optical elements coupled to thewavelength conversion member to receive the white light and tocollimate, steer, and project a first beam of the white light forilluminating one or more remote objects. The system also includes asecond set of optical elements configured to receive the second lightand generate a sensing light signal centered with the second peakwavelength and transmit a second beam of the sensing light signal forscanning over an area including the one or more remote objects and theirsurroundings. Moreover, the system includes a detector configured todetect reflected signals of the sensing light signal for mapping the oneor more remote objects.

Optionally, the gallium and nitrogen containing laser diode isconfigured to generate the first light with the first peak wavelength inviolet or blue color range.

Optionally, the sensing laser diode includes an infrared laser diode foremitting the third light with the third peak wavelength in infraredrange selected from one of 905 nm, 1000 nm, 1064 nm, 1300 nm, or 1550nm.

Optionally, the wavelength conversion member includes a yellow phosphorconfigured to generate the third light with the third peak wavelength inyellow color range.

Optionally, the wavelength conversion member further includes a bluephosphor configured to transmit the second light through substantiallywithout absorption.

Optionally, the first set of optical elements includes a firstcollimator to collimate the first beam of the white light to less than15 degrees with a first pattern and includes a steering element fordirecting the first beam with the first pattern to illuminate at leastpart of the one or more remote objects.

Optionally, the second set of optical elements includes a secondcollimator configured to collimate the second light as the second beamof the sensing light signal to less than 1 or 2 degrees with a secondpattern and includes a projector configured to project the second beamof the sensing light signal with the second pattern for mapping the oneor more target objects and their surroundings. The second pattern iswider than the first pattern.

Optionally, the projector includes one optical device selected from aMEMS controlled scanner, a digital-light processing (DLP) chip, and aliquid crystal on silicon (LCOS) chip for generating a mapping patternwith a plurality of pixels and dynamically scanning over the one or moreremote objects to generate a 3D map thereof.

Optionally, the processor includes a first modulator configured toprovide a first modulation signal with a first rate to drive the galliumand nitrogen containing laser diode to emit the first light with thefirst peak wavelength which is interrupted with a second rate. Thesecond rate is substantially synchronized with a delayed modulation rateof the second light of yellow color reemitted from the wavelengthconversion member.

Optionally, the first modulator is configured to provide the firstmodulation signal based on input data from an external source foramplitude modulation of the first light with the first peak wavelengthin violet or blue range.

Optionally, the processor includes a second modulator configured toprovide a second modulation signal to drive the sensing laser diode toemit the second light with the second peak wavelength and drive atransmitter component to transmit the sensing light signal withamplitude modulation.

Optionally, the second modulator is configured to provide a secondmodulation signal based on feedback information from the detector basedon reflected signals dynamically from the one or more remote objects.

Optionally, the detector includes at least one selected from aphotodiode, a photoresistor, a CCD camera, an antenna, a scanning mirroror a microdisplay coupled to a photodiode to convert the reflected lightsignals to electrical signals. The electrical signal is time-dependent.

Optionally, the detector further includes a signal receiver configuredto convert the electrical signals to an image of the one or more remoteobjects and their surroundings. The image is characterized substantiallyby the second peak wavelength and is time-dependent.

The present invention offers strong benefits over previous LIDARtechnologies by including a laser based illumination source, which couldbe a smart laser light source including spatial dynamic function,dynamic color or brightness, and/or visible light communication [VLC]such as LiFi. By combining laser based illumination systems with LIDAR,the LIDAR system can offer increased functionality, increasedsensitivity, smaller or more compact size, improved styling of theapparatus it is included within such as an automobile, improvedintegration in the apparatus it is included within such as anautomobile, and lower cost.

Merely by way of example, the present invention can be applied toapplications such as white lighting, white spot lighting, flash lights,automotive applications, automobile headlights or other lighting andcommunications functions, autonomous vehicles, all-terrain vehiclelighting, light sources used in recreational sports such as biking,surfing, running, racing, boating, light sources used for drones,planes, robots, other mobile or robotic applications, autonomous devicessuch as land, sea, or air vehicles and technology, safety, countermeasures in defense applications, multi-colored lighting, lighting forflat panels, medical, metrology, beam projectors and other displays,high intensity lamps, spectroscopy, entertainment, theater, music, andconcerts, analysis fraud detection and/or authenticating, tools, watertreatment, laser dazzlers, targeting, communications, LiFi, visiblelight communications (VLC), sensing, detecting, distance detecting,Light Detection And Ranging (LIDAR), transformations, transportations,leveling, curing and other chemical treatments, heating, cutting and/orablating, pumping other optical devices, other optoelectronic devicesand related applications, and source lighting and the like.

BRIEF DESCRIPTION OF THE FIGURES

The following drawings are merely examples for illustrative purposesaccording to various disclosed embodiments and are not intended to limitthe scope of the present invention.

FIG. 1 is a schematic diagram showing dependence of internal quantumefficiency in a laser diode on carrier concentration in the lightemitting layers of the device.

FIG. 2 is a plot of external quantum efficiency as a function of currentdensity for a high power blue laser diode compared to the high powerblue light emitting diode.

FIG. 3 is a simplified schematic diagram of a laser diode formed on agallium and nitrogen containing substrate with the cavity aligned in adirection ended with cleaved or etched mirrors according to someembodiments of the present invention.

FIG. 4 is a cross-sectional view of a laser device according to anembodiment of the present invention.

FIG. 5 is a schematic diagram illustrating a chip on submount (CoS)based on a conventional laser diode formed on gallium and nitrogencontaining substrate technology according to an embodiment of thepresent invention.

FIG. 6 is a simplified diagram illustrating a process of preparing anepitaxial wafer according to some embodiments of the present invention.

FIG. 7 is a schematic diagram illustrating a process comprised of firstforming the bond between an epitaxial material formed on the gallium andnitrogen containing substrate and then subjecting a sacrificial releasematerial to the PEC etch process to release the gallium and nitrogencontaining substrate according to some embodiments of the presentinvention.

FIG. 8 is a schematic representation of the die expansion process withselective area bonding according to some embodiments of the presentinvention.

FIG. 9 is an exemplary epitaxial structure for a laser diode deviceaccording to an embodiment of the present invention.

FIG. 10 is an example of a processed laser diode cross-section accordingto an embodiment of the present invention.

FIG. 11 is a schematic diagram illustrating a CoS based on lifted offand transferred epitaxial gallium and nitrogen containing layersaccording to an embodiment of this present invention.

FIG. 12A is a functional block diagram for a laser-based white lightsource containing a blue pump laser and a wavelength converting elementaccording to an embodiment of the present invention.

FIG. 12B is a functional block diagram for a laser-based white lightsource containing multiple blue pump lasers and a wavelength convertingelement according to another embodiment of the present invention.

FIG. 12C is a functional block diagram of a laser based white lightsource containing a blue pump laser, a wavelength converting element,and red and green laser diodes according to yet another embodiment ofthe present invention.

FIG. 12D is a functional block diagram of a laser based white lightsource containing blue, green and red laser devices and no wavelengthconverting element according to still another embodiment of the presentinvention.

FIG. 13A is a schematic diagram of a laser based white light sourceoperating in transmission mode and housed in a TO style packageaccording to an embodiment of the present invention.

FIG. 13B is a schematic diagram of a laser based white light sourceoperating in reflection mode and housed in a TO style package accordingto another embodiment of the present invention.

FIG. 13C is a schematic diagram of a laser based white light sourceoperating in reflection mode and housed in a butterfly-like stylepackage according to another embodiment of the present invention.

FIG. 13D is a schematic diagram of a laser based white light sourceoperating in transmission mode and housed in a butterfly-like stylepackage according to another embodiment of the present invention.

FIG. 14 is a simplified diagram illustrating a front view of a laserdevice with multiple cavity members according to an embodiment of thepresent invention.

FIG. 15 is a simplified diagram illustrating an individually addressablelaser package according to an embodiment of the present invention.

FIG. 16 is a simplified diagram illustrating a plurality of laser barsconfigured with optical combiners according to embodiments of thepresent invention.

FIG. 17 is a schematic of a free space mirror based laser combineraccording to an example of the present invention.

FIG. 18A is a schematic of an enclosed free space laser module accordingto an example of the present invention.

FIG. 18B is a schematic of an enclosed free space multi-chip lasermodule with an extended delivery fiber plus phosphor converter accordingto an example of the present invention.

FIG. 19A is a schematic diagram of a laser based white light sourceoperating in reflection mode according to an embodiment of the presentinvention.

FIG. 19B is a schematic diagram of a laser based white light sourceoperating in reflection mode according to another embodiment of thepresent invention.

FIG. 20A is a schematic diagram of a laser based white light sourceoperating in reflection mode in a surface mount package according to anembodiment of the present invention.

FIG. 20B is a schematic diagram of a laser based white light sourceoperating in reflection mode in a surface mount package according toanother embodiment of the present invention.

FIG. 20C is a schematic diagram of a laser based white light sourceoperating with side-pumped phosphor in a surface mount package accordingto another embodiment of the present invention.

FIG. 21 is a simplified block diagram of a LIDAR in related art.

FIG. 22A is a schematic diagram of an apparatus comprising both a LIDARsystem and laser based visible light source according to someembodiments of the present invention.

FIG. 22B is an exemplary diagram of using the apparatus in automobileaccording to some embodiments of the present invention.

FIG. 23 is a simplified schematic diagram of a laser light illuminationsystem integrated with a LIDAR system according to some embodiments ofthe present invention.

FIG. 24 is a simplified schematic diagram of a laser light illuminationsystem integrated with a LIDAR system according to some alternativeembodiments of the present invention.

FIG. 25 is a plot of absorption spectrum of pure water absorption as afunction of the wavelength of light.

FIG. 26 is schematic diagram of a mobile machine equipped with a laserillumination lighting system and a LIDAR system according to someembodiments of the present invention.

FIG. 27 is schematic diagram of a mobile machine equipped with a laserillumination lighting system and a LIDAR system according to somealternative embodiments of the present invention.

FIG. 28 is schematic diagram of a mobile machine equipped with a laserillumination lighting system and a LIDAR system according to somealternative embodiments of the present invention.

FIG. 29 is a simplified block diagram of a laser light illuminationsystem integrated with a LIDAR system including an additional LIDARmapping laser according to some embodiments of the present invention.

FIG. 30 is a simplified block diagram of a laser light illuminationsystem integrated with a LIDAR system including an additional LIDARmapping laser according to some alternative embodiments of the presentinvention.

FIG. 31 is a simplified block diagram of a laser light illuminationsystem integrated with a LIDAR system including an additional LIDARmapping laser according to some alternative embodiments of the presentinvention.

FIG. 32A is a functional block diagram of a laser based white lightsource enabled for visible light communication according to anembodiment of the present invention.

FIG. 32B is a functional block diagram of a laser based white lightsource enabled for visible light communication according to anotherembodiment of the present invention.

FIG. 33A is a functional block diagram for a dynamic light sourceaccording to some embodiments of the present invention.

FIG. 33B is a schematic of an enclosed dynamic light source with a beamsteering element according to an example of the present invention.

FIG. 34A is a schematic diagram of a scanned phosphor display withreflection architecture according to an embodiment of the presentinvention.

FIG. 34B is a schematic diagram of a scanned phosphor display withtransmission architecture according to an embodiment of the presentinvention.

FIG. 34C is a schematic diagram of a scanned phosphor display withreflection architecture according to an alternative embodiment of thepresent invention.

FIG. 35 is a schematic diagram of using a white laser light source basedon blue laser as projected light for visible light communicationaccording to some embodiments of the present invention.

FIG. 36A is a schematic of a composite wavelength converting elementenabling dynamic spatial control of light spot intensity and spectrumaccording to an embodiment of the present invention.

FIG. 36B is a schematic of the cross-section of the composite wavelengthconverting element according to an embodiment of the present invention.

FIG. 36C is a schematic of the cross-section of the composite wavelengthconverting element according to an embodiment of the present invention.

FIG. 37A is a functional block diagram for a laser-based smart-lightingsystem according to some embodiments of the present invention.

FIG. 37B is a functional diagram for a dynamic, laser-basedsmart-lighting system according to some embodiments of the presentinvention.

FIG. 38A is a schematic representation of a use case for someembodiments of the present invention where the output spatialdistribution of light intensity and color are altered in a predeterminedway based on the input from a sensor.

FIG. 38B is a schematic representation of a use case for someembodiments of the present invention where the output spatialdistribution of light intensity is altered in a predetermined way basedon the input from a sensor.

FIG. 38C is a schematic representation of a use case for someembodiments of the present invention where the output spatialdistribution of the light spectrum is altered in a predetermined waybased on the input from a sensor.

FIG. 39A is a schematic representation of a use case for someembodiments of the present invention where the apparatus is integratedwith an untethered, unmanned aerial vehicle or drone.

FIG. 39B is a schematic representation of a use case for someembodiments of the present invention where the apparatus is integratedwith a tethered balloon, tethered lighter than air craft, or tetheredunmanned aerial vehicle or drone.

FIG. 39C and FIG. 39D show a schematic representation of a use case forsome embodiments of the present invention where the apparatus isintegrated with a tethered balloon, tethered or untethered lighter thanair craft, or tethered or untethered unmanned aerial vehicle or drone.Multiple aerial platforms are used to provide continuous lighting andvisible light communication over an area.

DETAILED DESCRIPTION

The present invention provides system, apparatus configured with varioussensor-based feedback loops integrated with gallium and nitrogencontaining laser diodes based on a transferred gallium and nitrogencontaining material laser process and methods of manufacture and usethereof. Merely by examples, the invention provides remote andintegrated smart laser lighting devices and methods, projection displayand spatially dynamic lighting devices and methods, LIDAR, LiFi, andvisible light communication devices and methods, and variouscombinations of above in applications of general lighting, commerciallighting and display, automotive lighting and communication, defense andsecurity, industrial processing, and internet communications, andothers.

As background, while LED-based light sources offer great advantages overincandescent based sources, there are still challenges and limitationsassociated with LED device physics. The first limitation is the socalled “droop” phenomenon that plagues GaN based LEDs. The droop effectleads to power rollover with increased current density, which forcesLEDs to hit peak external quantum efficiency at very low currentdensities in the 10-200 A/cm² range. FIG. 1 shows a schematic diagram ofthe relationship between internal quantum efficiency [IQE] and carrierconcentration in the light emitting layers of a light emitting diode[LED] and light-emitting devices where stimulated emission issignificant such as laser diodes [LDs] or super-luminescent LEDs. IQE isdefined as the ratio of the radiative recombination rate to the totalrecombination rate in the device. At low carrier concentrationsShockley-Reed-Hall recombination at crystal defects dominatesrecombination rates such that IQE is low. At moderate carrierconcentrations, spontaneous radiative recombination dominates such thatIQE is relatively high. At high carrier concentrations, non-radiativeauger recombination dominates such that IQE is again relatively low. Indevices such as LDs or SLEDs, stimulated emission at very high carrierdensities leads to a fourth regime where IQE is relatively high. FIG. 2shows a plot of the external quantum efficiency [EQE] for a typical blueLED and for a high power blue laser diode. EQE is defined as the productof the IQE and the fraction of generated photons that are able to exitthe device. While the blue LED achieves a very high EQE at very lowcurrent densities, it exhibits very low EQE at high current densitiesdue to the dominance of auger recombination at high current densities.The LD, however, is dominated by stimulated emission at high currentdensities, and exhibits very high EQE. At low current densities, the LDhas relatively poor EQE due to re-absorption of photons in the device.Thus, to maximize efficiency of the LED based light source, the currentdensity must be limited to low values where the light output is alsolimited. The result is low output power per unit area of LED die [flux],which forces the use large LED die areas to meet the brightnessrequirements for most applications. For example, a typical LED basedlight bulb will require 3 mm² to 30 mm² of epi area.

A second limitation of LEDs is also related to their brightness, morespecifically it is related to their spatial brightness. A conventionalhigh brightness LED emits ˜1 W per mm² of epi area. With some advancesand breakthrough perhaps this can be increased up to 5-10× to 5-10 W permm² of epi area. Finally, LEDs fabricated on conventional c-plane GaNsuffer from strong internal polarization fields, which spatiallyseparate the electron and hole wave functions and lead to poor radiativerecombination efficiency. Since this phenomenon becomes more pronouncedin InGaN layers with increased indium content for increased wavelengthemission, extending the performance of UV or blue GaN-based LEDs to theblue-green or green regime has been difficult.

An exciting new class of solid-state lighting based on laser diodes israpidly emerging. Like an LED, a laser diode is a two-lead semiconductorlight source that that emits electromagnetic radiation. However, unlikethe output from an LED that is primarily spontaneous emission, theoutput of a laser diode is comprised primarily of stimulated emission.The laser diode contains a gain medium that functions to provideemission through the recombination of electron-hole pairs and a cavityregion that functions as a resonator for the emission from the gainmedium. When a suitable voltage is applied to the leads to sufficientlypump the gain medium, the cavity losses are overcome by the gain and thelaser diode reaches the so-called threshold condition, wherein a steepincrease in the light output versus current input characteristic isobserved. At the threshold condition, the carrier density clamps andstimulated emission dominates the emission. Since the droop phenomenonthat plagues LEDs is dependent on carrier density, the clamped carrierdensity within laser diodes provides a solution to the droop challenge.Further, laser diodes emit highly directional and coherent light withorders of magnitude higher spatial brightness than LEDs. For example, acommercially available edge emitting GaN-based laser diode can reliablyproduce about 2 W of power in an aperture that is 15 μm wide by about0.5 μm tall, which equates to over 250,000 W/mm². This spatialbrightness is over 5 orders of magnitude higher than LEDs or put anotherway, 10,000 times brighter than an LED.

Based on essentially all the pioneering work on GaN LEDs, visible laserdiodes based on GaN technology have rapidly emerged over the past 20years. Currently the only viable direct blue and green laser diodestructures are fabricated from the wurtzite AlGaInN material system. Themanufacturing of light emitting diodes from GaN related materials isdominated by the heteroepitaxial growth of GaN on foreign substratessuch as Si, SiC and sapphire. Laser diode devices operate at such highcurrent densities that the crystalline defects associated withheteroepitaxial growth are not acceptable. Because of this, very lowdefect-density, free-standing GaN substrates have become the substrateof choice for GaN laser diode manufacturing. Unfortunately, such bulkGaN substrates are costly and not widely available in large diameters.For example, 2″ diameter is the most common laser-quality bulk GaNc-plane substrate size today with recent progress enabling 4″ diameter,which are still relatively small compared to the 6″ and greaterdiameters that are commercially available for mature substratetechnologies. Further details of the present invention can be foundthroughout the present specification and more particularly below.

Additional benefits are achieved over pre-existing techniques using thepresent invention. In particular, the present invention enables acost-effective white light source. In a specific embodiment, the presentoptical device can be manufactured in a relatively simple and costeffective manner. Depending upon the embodiment, the present apparatusand method can be manufactured using conventional materials and/ormethods according to one of ordinary skill in the art. In someembodiments of this invention the gallium and nitrogen containing laserdiode source is based on c-plane gallium nitride material and in otherembodiments the laser diode is based on nonpolar or semipolar galliumand nitride material. In one embodiment the white source is configuredfrom a chip on submount (CoS) with an integrated phosphor on thesubmount to form a chip and phosphor on submount (CPoS) white lightsource. In some embodiments intermediate submount members may beincluded. In some embodiments the laser diode and the phosphor memberare supported by a common support member such as a package base. In thisembodiment there could be submount members or additional support membersincluded between the laser diode and the common support member.Similarly there could be submount members or additional support membersincluded between the phosphor member and the common support member.

In various embodiments, the laser device and phosphor device areco-packaged or mounted on a common support member with or withoutintermediate submounts and the phosphor materials are operated in atransmissive mode, a reflective mode, or a side-pumped mode to result ina white emitting laser-based light source. In additional variousembodiments, the electromagnetic radiation from the laser device isremotely coupled to the phosphor device through means such as free spacecoupling or coupling with a waveguide such as a fiber optic cable orother solid waveguide material, and wherein the phosphor materials areoperated in a transmissive mode, a reflective mode, or a side-pumpedmode to result in a white emitting laser-based light source. Merely byway of example, the invention can be applied to applications such aswhite lighting, white spot lighting, flash lights, automobileheadlights, all-terrain vehicle lighting, flash sources such as cameraflashes, light sources used in recreational sports such as biking,surfing, running, racing, boating, light sources used for drones,planes, robots, other mobile or robotic applications, safety, countermeasures in defense applications, multi-colored lighting, lighting forflat panels, medical, metrology, beam projectors and other displays,high intensity lamps, spectroscopy, entertainment, theater, music, andconcerts, analysis fraud detection and/or authenticating, tools, watertreatment, laser dazzlers, targeting, communications, LiFi, visiblelight communications (VLC), sensing, detecting, distance detecting,Light Detection And Ranging (LIDAR), transformations, autonomousvehicles, transportations, leveling, curing and other chemicaltreatments, heating, cutting and/or ablating, pumping other opticaldevices, other optoelectronic devices and related applications, andsource lighting and the like.

Laser diodes are ideal as phosphor excitation sources. With a spatialbrightness (optical intensity per unit area) greater than 10,000 timeshigher than conventional LEDs and the extreme directionality of thelaser emission, laser diodes enable characteristics unachievable by LEDsand other light sources. Specifically, since the laser diodes outputbeams carrying over 1 W, over 5 W, over 10 W, or even over 100 W can befocused to very small spot sizes of less than 1 mm in diameter, lessthan 500 μm in diameter, less than 100 μm in diameter, or even less than50 μm in diameter, power densities of over 1 W/mm², 100 W/mm², or evenover 2,500 W/mm² can be achieved. When this very small and powerful beamof laser excitation light is incident on a phosphor material theultimate point source of white light can be achieved. Assuming aphosphor conversion ratio of 200 lumens of emitted white light peroptical watt of excitation light, a 5 W excitation power could generate1000 lumens in a beam diameter of 100 μm, or 50 μm, or less. Such apoint source is game changing in applications such as spotlighting orrange finding where parabolic reflectors or lensing optics can becombined with the point source to create highly collimated white lightspots that can travel drastically higher distances than ever possiblebefore using LEDs or bulb technology.

In some embodiments of the present invention the gallium and nitrogencontaining light emitting device may not be a laser device, but insteadmay be configured as a superluminescent diode or superluminescent lightemitting diode (SLED) device. For the purposes of this invention, a SLEDdevice and laser diode device can be used interchangeably. A SLED issimilar to a laser diode as it is based on an electrically drivenjunction that when injected with current becomes optically active andgenerates amplified spontaneous emission (ASE) and gain over a widerange of wavelengths. When the optical output becomes dominated by ASEthere is a knee in the light output versus current (LI) characteristicwherein the unit of light output becomes drastically larger per unit ofinjected current. This knee in the LI curve resembles the threshold of alaser diode, but is much softer. The advantage of a SLED device is thatSLED it can combine the unique properties of high optical emission powerand extremely high spatial brightness of laser diodes that make themideal for highly efficient long throw illumination and high brightnessphosphor excitation applications with a broad spectral width of (>5 nm)that provides for an improved eye safety and image quality in somecases. The broad spectral width results in a low coherence lengthsimilar to an LED. The low coherence length provides for an improvedsafety such has improved eye safety. Moreover, the broad spectral widthcan drastically reduce optical distortions in display or illuminationapplications. As an example, the well-known distortion pattern referredto as “speckle” is the result of an intensity pattern produced by themutual interference of a set of wavefronts on a surface or in a viewingplane. The general equations typically used to quantify the degree ofspeckle are inversely proportional to the spectral width. In the presentspecification, both a laser diode (LD) device and a superluminescentlight emitting diode (SLED) device are sometime simply referred to“laser device”.

A gallium and nitrogen containing laser diode (LD) or super luminescentlight emitting diode (SLED) may comprise at least a gallium and nitrogencontaining device having an active region and a cavity member and arecharacterized by emitted spectra generated by the stimulated emission ofphotons. In some embodiments a laser device emitting red laser light,i.e. light with wavelength between about 600 nm to 750 nm, are provided.These red laser diodes may comprise at least a gallium phosphorus andarsenic containing device having an active region and a cavity memberand are characterized by emitted spectra generated by the stimulatedemission of photons. The ideal wavelength for a red device for displayapplications is ˜635 nm, for green ˜530 nm and for blue 440-470 nm.There may be tradeoffs between what colors are rendered with a displayusing different wavelength lasers and also how bright the display is asthe eye is more sensitive to some wavelengths than to others.

In some embodiments according to the present invention, multiple laserdiode sources are configured to excite the same phosphor or phosphornetwork. Combining multiple laser sources can offer many potentialbenefits according to this invention. First, the excitation power can beincreased by beam combining to provide a more powerful excitation spitand hence produce a brighter light source. In some embodiments, separateindividual laser chips are configured within the laser-phosphor lightsource. By including multiple lasers emitting 1 W, 2 W, 3 W, 4 W, 5 W ormore power each, the excitation power can be increased and hence thesource brightness would be increased. For example, by including two 3 Wlasers exciting the same phosphor area, the excitation power can beincreased to 6 W for double the white light brightness. In an examplewhere about 200 lumens of white are generated per 1 watt of laserexcitation power, the white light output would be increased from 600lumens to 1200 lumens. Beyond scaling the power of each single laserdiode emitter, the total luminous flux of the white light source can beincreased by continuing to increasing the total number of laser diodes,which can range from 10 s, to 100 s, and even to 1000 s of laser diodeemitters resulting in 10 s to 100 s of kW of laser diode excitationpower. Scaling the number of laser diode emitters can be accomplished inmany ways such as including multiple lasers in a co-package, spatialbeam combining through conventional refractive optics or polarizationcombining, and others. Moreover, laser diode bars or arrays, andmini-bars can be utilized where each laser chip includes many adjacentlaser diode emitters. For example, a bar could include from 2 to 100laser diode emitters spaced from about 10 microns to about 400 micronsapart. Similarly, the reliability of the source can be increased byusing multiple sources at lower drive conditions to achieve the sameexcitation power as a single source driven at more harsh conditions suchas higher current and voltage.

A additional advantage of combining the emission from multiple laserdiode emitters is the potential for a more circular spot by rotating thefirst free space diverging elliptical laser beam by 90 degrees relativeto the second free space diverging elliptical laser beam and overlappingthe centered ellipses on the phosphor. Alternatively, a more circularspot can be achieved by rotating the first free space divergingelliptical laser beam by 180 degrees relative to the second free spacediverging elliptical laser beam and off-centered overlapping theellipses on the phosphor to increase spot diameter in slow axisdiverging direction. In another configuration, more than 2 lasers areincluded and some combination of the above described beam shaping spotgeometry shaping is achieved. A third and important advantage is thatmultiple color lasers in an emitting device can significantly improvecolor quality (CRI and CQS) by improving the fill of the spectra in theviolet/blue and cyan region of the visible spectrum. For example, two ormore blue excitation lasers with slightly detuned wavelengths (e.g. 5nm, 10 nm, 15 nm, etc.) can be included to excite a yellow phosphor andcreate a larger blue spectrum.

As used herein, the term GaN substrate is associated with GroupDI-nitride based materials including GaN, InGaN, AlGaN, or other GroupIII containing alloys or compositions that are used as startingmaterials. Such starting materials include polar GaN substrates (i.e.,substrate where the largest area surface is nominally an (h k l) planewherein h=k, and l is non-zero), non-polar GaN substrates (i.e.,substrate material where the largest area surface is oriented at anangle ranging from about 80-100 degrees from the polar orientationdescribed above towards an (h k l) plane wherein l=0, and at least oneof h and k is non-zero) or semi-polar GaN substrates (i.e., substratematerial where the largest area surface is oriented at an angle rangingfrom about +0.1 to 80 degrees or 110-179.9 degrees from the polarorientation described above towards an (h k l) plane wherein l=0, and atleast one of h and k is non-zero). Of course, there can be othervariations, modifications, and alternatives.

The laser diode device can be fabricated on a conventional orientationof a gallium and nitrogen containing film or substrate (e.g., GaN) suchas the polar c-plane, on a nonpolar orientation such as the in-plane, oron a semipolar orientation such as the {30-31}, {20-21}, {30-32},{11-22}, {10-11}, {30-3-1}, {20-2-1}, {30-3-2}, or offcuts of any ofthese polar, nonpolar, and semipolar planes within +/−10 degrees towardsa c-plane, and/or +/−10 degrees towards an a-plane, and/or +/−10 degreestowards an m-plane. In some embodiments, a gallium and nitrogencontaining laser diode laser diode comprises a gallium and nitrogencontaining substrate. The substrate member may have a surface region onthe polar {0001} plane (c-plane), nonpolar plane (m-plane, a-plane), andsemipolar plain ({11-22}, {10-1-1}, {20-21}, {30-31}) or other planes ofa gallium and nitrogen containing substrate. The laser device can beconfigured to emit a laser beam characterized by one or more wavelengthsfrom about 390 nm to about 540 run.

FIG. 3 is a simplified schematic diagram of a laser diode formed on agallium and nitrogen containing substrate with the cavity aligned in adirection ended with cleaved or etched mirrors according to someembodiments of the present invention. In an example, the substratesurface 101 is a polar c-plane and the laser stripe region 110 ischaracterized by a cavity orientation substantially in an m-direction10, which is substantially normal to an a-direction 20, but can beothers such as cavity alignment substantially in the a-direction. Thelaser strip region 110 has a first end 107 and a second end 109 and isformed on an m-direction on a {0001} gallium and nitrogen containingsubstrate having a pair of cleaved or etched mirror structures, whichface each other. In another example, the substrate surface 101 is asemipolar plane and the laser stripe region 110 is characterized by acavity orientation substantially in a projection of a c-direction 10,which is substantially normal to an a-direction 20, but can be otherssuch as cavity alignment substantially in the a-direction. The laserstrip region 110 has a first end 107 and a second end 109 and is formedon au semipolar substrate such as a {40-41}, {30-31}, {20-21}, {40-4-1},{30-3-1}, {20-2-1}, {20-21}, or an offcut of these planes within +1-5degrees from the c-plane and a-plane gallium and nitrogen containingsubstrate. Optionally, the gallium nitride substrate member is a bulkGaN substrate characterized by having a nonpolar or semipolarcrystalline surface region, but can be others. The bulk GaN substratemay have a surface dislocation density below 10⁵ cm⁻² or 10⁵ to 10⁷cm⁻². The nitride crystal or wafer may comprise Al_(x)In_(y)Ga_(1-x-y)N,where 0≤x, y, x+y≤1. In one specific embodiment, the nitride crystalcomprises GaN. In a embodiments, the GaN substrate has threadingdislocations, at a concentration between about 10⁵ cm⁻² and about 10⁸cm⁻², in a direction that is substantially orthogonal or oblique withrespect to the surface.

The exemplary laser diode devices in FIG. 3 have a pair of cleaved oretched mirror structures 109 and 107, which face each other. The firstcleaved or etched facet 109 comprises a reflective coating and thesecond cleaved or etched facet 107 comprises no coating, anantireflective coating, or exposes gallium and nitrogen containingmaterial. The first cleaved or etched facet 109 is substantiallyparallel with the second cleaved or etched facet 107. The first andsecond cleaved facets 109 and 107 are provided by a scribing andbreaking process according to an embodiment or alternatively by etchingtechniques using etching technologies such as reactive ion etching(RIE), inductively coupled plasma etching (ICP), or chemical assistedion beam etching (CAME), or other method. The reflective coating isselected from silicon dioxide, hafnia, and titania, tantalum pentoxide,zirconia, aluminum oxide, aluminum nitride, and aluminum oxynitrideincluding combinations, and the like. Depending upon the design, themirror surfaces can also comprise an anti-reflective coating.

In a specific embodiment, the method of facet formation includessubjecting the substrates to a laser for pattern formation. In apreferred embodiment, the pattern is configured for the formation of apair of facets for a ridge lasers. In a preferred embodiment, the pairof facets face each other and are in parallel alignment with each other.In a preferred embodiment, the method uses a UV (355 nm) laser to scribethe laser bars. In a specific embodiment, the laser is configured on asystem, which allows for accurate scribe lines configured in a differentpatterns and profiles. In a embodiments, the laser scribing can beperformed on the back-side, front-side, or both depending upon theapplication. Of course, there can be other variations, modifications,and alternatives.

In a specific embodiment, the method uses backside laser scribing or thelike. With backside laser scribing, the method preferably forms acontinuous line laser scribe that is perpendicular to the laser bars onthe backside of the GaN substrate. In a specific embodiment, the laserscribe is generally about 15-20 μm deep or other suitable depth.Preferably, backside scribing can be advantageous. That is, the laserscribe process does not depend on the pitch of the laser bars or otherlike pattern. Accordingly, backside laser scribing can lead to a higherdensity of laser bars on each substrate according to a preferredembodiment. In a specific embodiment, backside laser scribing, however,may lead to residue from the tape on the facets. In a specificembodiment, backside laser scribe often requires that the substratesface down on the tape. With front-side laser scribing, the backside ofthe substrate is in contact with the tape. Of course, there can be othervariations, modifications, and alternatives.

It is well known that etch techniques such as chemical assisted ion beametching (CAME), inductively coupled plasma (ICP) etching, or reactiveion etching (RIE) can result in smooth and vertical etched sidewallregions, which could serve as facets in etched facet laser diodes. Inthe etched facet process a masking layer is deposited and patterned onthe surface of the wafer. The etch mask layer could be comprised ofdielectrics such as silicon dioxide (SiO₂), silicon nitride(Si_(x)N_(y)), a combination thereof or other dielectric materials.Further, the mask layer could be comprised of metal layers such as Ni orCr, but could be comprised of metal combination stacks or stackscomprising metal and dielectrics. In another approach, photoresist maskscan be used either alone or in combination with dielectrics and/ormetals. The etch mask layer is patterned using conventionalphotolithography and etch steps. The alignment lithography could beperformed with a contact aligner or stepper aligner. Suchlithographically defined mirrors provide a high level of control to thedesign engineer. After patterning of the photoresist mask on top of theetch mask is complete, the patterns in then transferred to the etch maskusing a wet etch or dry etch technique. Finally, the facet pattern isthen etched into the wafer using a dry etching technique selected fromCAIBE, ICP, RIE and/or other techniques. The etched facet surfaces mustbe highly vertical of between about 87 and about 93 degrees or betweenabout 89 and about 91 degrees from the surface plane of the wafer. Theetched facet surface region must be very smooth with root mean squareroughness values of less than about 50 nm, 20 nm, 5 nm, or 1 nm. Lastly,the etched must be substantially free from damage, which could act asnonradiative recombination centers and hence reduce the catastrophicoptical mirror damage (COMD) threshold. CAIBE is known to provide verysmooth and low damage sidewalls due to the chemical nature of the etch,while it can provide highly vertical etches due to the ability to tiltthe wafer stage to compensate for any inherent angle in etch.

The laser stripe 110 is characterized by a length and width. The lengthranges from about 50 μm to about 3000 μm, but is preferably betweenabout 10 μm and about 400 μm, between about 400 μm and about 800 μm, orabout 800 μm and about 1600 μm, but could be others. The stripe also hasa width ranging from about 0.5 μm to about 50 μm, but is preferablybetween about 0.8 μm and about 2.5 μm for single lateral mode operationor between about 2.5 μm and about 50 μm for multi-lateral modeoperation, but can be other dimensions. In a specific embodiment, thepresent device has a width ranging from about 0.5 μm to about 1.5 μm, awidth ranging from about 1.5 μm to about 3.0 μm, a width ranging fromabout 3.0 μm to about 50 μm, and others. In a specific embodiment, thewidth is substantially constant in dimension, although there may beslight variations. The width and length are often formed using a maskingand etching process, which are commonly used in the art.

The laser stripe region 110 is provided by an etching process selectedfrom dry etching or wet etching. The device also has au overlyingdielectric region, which exposes a p-type contact region. Overlying thecontact region is a contact material, which may be metal or a conductiveoxide or a combination thereof. The p-type electrical contact may bedeposited by thermal evaporation, electron beam evaporation,electroplating, sputtering, or another suitable technique. Overlying thepolished region of the substrate is a second contact material, which maybe metal or a conductive oxide or a combination thereof and whichcomprises the n-type electrical contact. The n-type electrical contactmay be deposited by thermal evaporation, electron beam evaporation,electroplating, sputtering, or another suitable technique.

In a specific embodiment, the laser device may emit red light with acenter wavelength between 600 nm and 750 nm. Such a device may compriselayers of varying compositions of Al_(x)In_(y)Ga_(1-x-y)As_(z)P_(1-z),where x+y≤1 and z≤1. The red laser device comprises at least an n-typeand p-type cladding layer, an n-type SCH of higher refractive index thanthe n-type cladding, a p-type SCH of higher refractive index than thep-type cladding and an active region where light is emitted. In aspecific embodiment, the laser stripe is provided by an etching processselected from dry etching or wet etching. In a preferred embodiment, theetching process is dry, but can be others. The device also has anoverlying dielectric region, which exposes the contact region. In aspecific embodiment, the dielectric region is an oxide such as silicondioxide, but can be others. Of course, there can be other variations,modifications, and alternatives. The laser stripe is characterized by alength and width. The length ranges from about 50 μm to about 3000 μm,but is preferably between 10 μm and 400 μm, between about 400 μm and 800μm, or about 800 μm and 1600 μm, but could be others such as greaterthan 1600 μm. The stripe also has a width ranging from about 0.5 μm toabout 80 μm, but is preferably between 0.8 μm and 2.5 μm for singlelateral mode operation or between 2.5 μm and 60 μm for multi-lateralmode operation, but can be other dimensions. The laser strip region hasa first end and a second end having a pair of cleaved or etched mirrorstructures, which face each other. The first facet comprises areflective coating and the second facet comprises no coating, anantireflective coating, or exposes gallium and nitrogen containingmaterial. The first facet is substantially parallel with the secondcleaved or etched facet.

Given the high gallium and nitrogen containing substrate costs,difficulty in scaling up gallium and nitrogen containing substrate size,the inefficiencies inherent in the processing of small wafers, andpotential supply limitations it becomes extremely desirable to maximizeutilization of available gallium and nitrogen containing substrate andoverlying epitaxial material. In the fabrication of lateral cavity laserdiodes, it is typically the case that minimum die size is determined bydevice components such as the wire bonding pads or mechanical handlingconsiderations, rather than by laser cavity widths. Minimizing die sizeis critical to reducing manufacturing costs as smaller die sizes allow agreater number of devices to be fabricated on a single wafer in a singleprocessing run. The current invention is a method of maximizing thenumber of devices which can be fabricated from a given gallium andnitrogen containing substrate and overlying epitaxial material byspreading out the epitaxial material onto a carrier wafer via a dieexpansion process.

Similar to an edge emitting laser diode, a SLED is typically configuredas an edge-emitting device wherein the high brightness, highlydirectional optical emission exits a waveguide directed outward from theside of the semiconductor chip. SLEDs are designed to have high singlepass gain or amplification for the spontaneous emission generated alongthe waveguide. However, unlike laser diodes, they are designed toprovide insufficient feedback to in the cavity to achieve the lasingcondition where the gain equals the total losses in the waveguidecavity. In a typical example, at least one of the waveguide ends orfacets is designed to provide very low reflectivity back into thewaveguide. Several methods can be used to achieve reduced reflectivityon the waveguide end or facet. In one approach an optical coating isapplied to at least one of the facets, wherein the optical coating isdesigned for low reflectivity such as less than 1%, less than 0.1%, lessthan 0.001%, or less than 0.0001% reflectivity. In another approach forreduced reflectivity the waveguide ends are designed to be tilted orangled with respect to the direction of light propagation such that thelight that is reflected back into the chip does not constructivelyinterfere with the light in the cavity to provide feedback. The tiltangle must be carefully designed around a null in the reflectivityversus angle relationship for optimum performance. The tilted or angledfacet approach can be achieved in a number of ways including providingan etched facet that is designed with an optimized angle lateral anglewith respect to the direction of light propagation. The angle of thetilt is pre-determined by the lithographically defined etched facetpatter. Alternatively, the angled output could be achieved by curvingand/or angling the waveguide with respect to a cleaved facet that formson a pre-determined crystallographic plane in the semiconductor chip.Another approach to reduce the reflectivity is to provide a roughened orpatterned surface on the facet to reduce the feedback to the cavity. Theroughening could be achieved using chemical etching and/or a dryetching, or with an alternative technique. Of course there may be othermethods for reduced feedback to the cavity to form a SLED device. Inmany embodiments a number of techniques can be used in combination toreduce the facet reflectivity including using low reflectivity coatingsin combination with angled or tilted output facets with respect to thelight propagation.

In a specific embodiment on a nonpolar Ga-containing substrate, thedevice is characterized by a spontaneously emitted light is polarized insubstantially perpendicular to the c-direction. In a preferredembodiment, the spontaneously emitted light is characterized by apolarization ratio of greater than 0.1 to about 1 perpendicular to thec-direction. In a preferred embodiment, the spontaneously emitted lightcharacterized by a wavelength ranging from about 430 nanometers to about470 nm to yield a blue emission, or about 500 nanometers to about 540nanometers to yield a green emission, and others. For example, thespontaneously emitted light can be violet (e.g., 395 to 420 nanometers),blue (e.g., 420 to 470 nm); green (e.g., 500 to 540 nm), or others. In apreferred embodiment, the spontaneously emitted light is highlypolarized and is characterized by a polarization ratio of greater than0.4. In another specific embodiment on a semipolar {20-21} Ga-containingsubstrate, the device is also characterized by a spontaneously emittedlight is polarized in substantially parallel to the a-direction orperpendicular to the cavity direction, which is oriented in theprojection of the c-direction.

In a specific embodiment, the present invention provides an alternativedevice structure capable of emitting 501 nm and greater light in a ridgelaser embodiment. The device is provided with a of the followingepitaxially grown elements:

-   -   an n-GaN or n-AlGaN cladding layer with a thickness from 100 nm        to 3000 nm with Si doping level of 5×10¹⁷ cm⁻³ to 3×10¹⁸ cm⁻³;    -   an n-side SCH layer comprised of InGaN with molar fraction of        indium of between 2% and 15% and thickness from 20 nm to 250 nm;    -   a single quantum well or a multiple quantum well active region        comprised of at least two 2.0 nm to 8.5 nm InGaN quantum wells        separated by 1.5 nm and greater, and optionally up to about 12        nm, GaN or InGaN barriers;    -   a p-side SCH layer comprised of InGaN with molar a fraction of        indium of between 1% and 10% and a thickness from 15 nm to 250        nm or an upper GaN-guide layer;    -   an electron blocking layer comprised of AlGaN with molar        fraction of aluminum of between 0% and 22% and thickness from 5        nm to 20 nm and doped with Mg;    -   a p-GaN or p-AlGaN cladding layer with a thickness from 400 nm        to 1500 nm with Mg doping level of 2×10¹⁷ cm⁻³ to 2×10¹⁹ cm-³;        and    -   a p++-GaN contact layer with a thickness from 20 nm to 40 nm        with Mg doping level of 1×10¹⁹ cm⁻³ to 1×10²¹ cm⁻³.

A gallium and nitrogen containing laser diode laser device may alsoinclude other structures, such as a surface ridge architecture, a buriedheterostructure architecture, and/or a plurality of metal electrodes forselectively exciting the active region. For example, the active regionmay comprise first and second gallium and nitrogen containing claddinglayers and an indium and gallium containing emitting layer positionedbetween the first and second cladding layers. A laser device may furtherinclude an n-type gallium and nitrogen containing material and an n-typecladding material overlying the n-type gallium and nitrogen containingmaterial. In a specific embodiment, the device also has an overlyingn-type gallium nitride layer, an active region, and an overlying p-typegallium nitride layer structured as a laser stripe region. Additionally,the device may also include an n-side separate confinementhetereostructure (SCH), p-side guiding layer or SCH, p-AlGaN EBL, amongother features. In a specific embodiment, the device also has a p++ typegallium nitride material to form a contact region. In a specificembodiment, the p++ type contact region has a suitable thickness and mayrange from about 10 nm 50 nm, or other thicknesses. In a specificembodiment, the doping level can be higher than the p-type claddingregion and/or bulk region. In a specific embodiment, the p++ type regionhas doping concentration ranging from about 10¹⁹ to 10²¹ Mg/am³, andothers. The p++ type region preferably causes tunneling between thesemiconductor region and overlying metal contact region. In a specificembodiment, each of these regions is formed using at least an epitaxialdeposition technique of metal organic chemical vapor deposition (MOCVD),molecular beam epitaxy (MBE), or other epitaxial growth techniquessuitable for GaN growth. In a specific embodiment, the epitaxial layeris a high quality epitaxial layer overlying the n-type gallium nitridelayer. In some embodiments the high quality layer is doped, for example,with Si or O to form n-type material, with a dopant concentrationbetween about 10¹⁶ cm⁻³ and 10²⁰ cm⁻³.

FIG. 4 is a cross-sectional view of a laser device 200 according to someembodiments of the present disclosure. As shown, the laser deviceincludes gallium nitride substrate 203, which has an underlying n-typemetal back contact region 201. For example, the substrate 203 may becharacterized by a semipolar or nonpolar orientation. The device alsohas an overlying n-type gallium nitride layer 205, an active region 207,and an overlying p-type gallium nitride layer structured as a laserstripe region 209. Each of these regions is formed using at least anepitaxial deposition technique of metal organic chemical vapordeposition (MOCVD), molecular beam epitaxy (MBE), or other epitaxialgrowth techniques suitable for GaN growth. The epitaxial layer is a highquality epitaxial layer overlying the n-type gallium nitride layer. Insome embodiments the high quality layer is doped, for example, with Sior O to form n-type material, with a dopant concentration between about10¹⁶ cm⁻³ and 10²⁰ cm⁻³.

An n-type Al_(u)In_(v)Ga_(1-u-v)N layer, where 0≤u, v, u+v≤1, isdeposited on the substrate. The carrier concentration may lie in therange between about 10¹⁶ cm⁻³ and 10²⁰ cm⁻³. The deposition may beperformed using metalorganic chemical vapor deposition (MOCVD) ormolecular beam epitaxy (MBE).

For example, the bulk GaN substrate is placed on a susceptor in an MOCVDreactor. After closing, evacuating, and back-filling the reactor (orusing a load lock configuration) to atmospheric pressure, the susceptoris heated to a temperature between about 1000 and about 1200 degreesCelsius in the presence of a nitrogen-containing gas. The susceptor isheated to approximately 900 to 1200 degrees Celsius under flowingammonia. A flow of a gallium-containing metalorganic precursor, such astrimethylgallium (TMG) or triethylgallium (TEG) is initiated, in acarrier gas, at a total rate between approximately 1 and 50 standardcubic centimeters per minute (sccm). The carrier gas may comprisehydrogen, helium, nitrogen, or argon. The ratio of the flow rate of thegroup V precursor (ammonia) to that of the group III precursor(trimethylgallium, triethylgallium, trimethylindium, trimethylaluminum)during growth is between about 2000 and about 12000. A flow of disilanein a carrier gas, with a total flow rate of between about 0.1 sccm and10 sccm, is initiated.

In one embodiment, the laser stripe region is p-type gallium nitridelayer 209. The laser stripe is provided by a dry etching process, butwet etching can be used. The dry etching process is an inductivelycoupled process using chlorine bearing species or a reactive ion etchingprocess using similar chemistries. The chlorine bearing species arecommonly derived from chlorine gas or the like. The device also has anoverlying dielectric region, which exposes a contact region 213. Thedielectric region is an oxide such as silicon dioxide or siliconnitride, and a contact region is coupled to an overlying metal layer215. The overlying metal layer is preferably a multilayered structurecontaining gold and platinum (Pt/Au), palladium and gold (Pd/Au), ornickel gold (Ni/Au), or a combination thereof. In some embodiments,barrier layers and more complex metal stacks are included.

Active region 207 preferably includes one to ten quantum well regions ora double heterostructure region for light emission. Following depositionof the n-type Al_(u)In_(v)Ga_(1-u-v)N layer to achieve a desiredthickness, an active layer is deposited. The quantum wells arepreferably InGaN with GaN, AlGaN, InAlGaN, or InGaN barrier layersseparating them. In other embodiments, the well layers and barrierlayers comprise Al_(w)In_(x)Ga_(1-w-x)N and Al_(y)In_(z)Ga_(1-y-z)N,respectively, where 0≤w, x, y, z, w+x, y+z≤1, where w<u, y and/or x>v, zso that the bandgap of the well layer(s) is less than that of thebarrier layer(s) and the n-type layer. The well layers and barrierlayers each have a thickness between about 1 nm and about 20 nm. Thecomposition and structure of the active layer are chosen to providelight emission at a preselected wavelength. The active layer may be leftundoped (or unintentionally doped) or may be doped n-type or p-type.

The active region can also include an electron blocking region, and aseparate confinement heterostructure. The electron-blocking layer maycomprise Al_(s)In_(t)Ga_(1-s-t)N, where 0≤s, t, s+t≤1, with a higherbandgap than the active layer, and may be doped p-type. In one specificembodiment, the electron blocking layer includes AlGaN. In anotherembodiment, the electron blocking layer includes an AlGaN/GaNsuper-lattice structure, comprising alternating layers of AlGaN and GaN,each with a thickness between about 0.2 nm and about 5 nm.

As noted, the p-type gallium nitride or aluminum gallium nitridestructure is deposited above the electron blocking layer and activelayer(s). The p-type layer may be doped with Mg, to a level betweenabout 10¹⁶ cm⁻¹ and 10²² cm⁻³, with a thickness between about 5 nm andabout 1000 nm. The outermost 1-50 nm of the p-type layer may be dopedmore heavily than the rest of the layer, so as to enable an improvedelectrical contact. The device also has an overlying dielectric region,for example, silicon dioxide, which exposes the contact region 213.

The metal contact is made of suitable material such as silver, gold,aluminum, nickel, platinum, rhodium, palladium, chromium, or the like.The contact may be deposited by thermal evaporation, electron beamevaporation, electroplating, sputtering, or another suitable technique.In a preferred embodiment, the electrical contact serves as a p-typeelectrode for the optical device. In another embodiment, the electricalcontact serves as an n-type electrode for the optical device. The laserdevices illustrated in FIG. 3 and FIG. 4 and described above aretypically suitable for relative low-power applications.

In various embodiments, the present invention realizes high output powerfrom a diode laser is by widening a portions of the laser cavity memberfrom the single lateral mode regime of 1.0-3.0 μm to the multi-lateralmode range 5.0-20 μm. In some cases, laser diodes having cavities at awidth of 50 μm or greater are employed.

The laser stripe length, or cavity length ranges from 100 to 3000 μm andemploys growth and fabrication techniques such as those described inU.S. patent application Ser. No. 12/759,273, filed Apr. 13, 2010, whichis incorporated by reference herein. As an example, laser diodes arefabricated on nonpolar or semipolar gallium containing substrates, wherethe internal electric fields are substantially eliminated or mitigatedrelative to polar c-plane oriented devices. It is to be appreciated thatreduction in internal fields often enables more efficient radiativerecombination. Further, the heavy hole mass is expected to be lighter onnonpolar and semipolar substrates, such that better gain properties fromthe lasers can be achieved.

Optionally, FIG. 4 illustrates an example cross-sectional diagram of agallium and nitrogen based laser diode device. The epitaxial devicestructure is formed on top of the gallium and nitrogen containingsubstrate member 203. The substrate member may be n-type doped with Oand/or Si doping. The epitaxial structures will contain n-side layers205 such as an n-type buffer layer comprised of GaN, AlGaN, AlINGaN, orInGaN and n-type cladding layers comprised of GaN, AlGaN, or AlInGaN.The n-typed layers may have thickness in the range of 0.3 μm to about 3μm or to about 5 μm and may be doped with an n-type carriers such as Sior O to concentrations between 1×10¹⁶ cm⁻³ to 1×10¹⁹ cm⁻³. Overlying then-type layers is the active region and waveguide layers 207. This regioncould contain an n-side waveguide layer or separate confinementheterostructure (SCH) such as InGaN to help with optical guiding of themode. The InGaN layer be comprised of 1 to 15% molar fraction of InNwith a thickness ranging from about 30 nm to about 250 nm and may bedoped with an n-type species such as Si. Overlying the SCH layer is thelight emitting regions which could be comprised of a doubleheterostructure or a quantum well active region. A quantum well activeregion could be comprised of 1 to 10 quantum wells ranging in thicknessfrom 1 nm to 20 nm comprised of InGaN. Barrier layers comprised of GaN,InGaN, or AlGaN separate the quantum well light emitting layers. Thebarriers range in thickness from 1 nm to about 25 nm. Overlying thelight emitting layers are optionally an AlGaN or InAlGaN electronblocking layer with 5% to about 35% AlN and optionally doped with ap-type species such as Mg. Also optional is a p-side waveguide layer orSCH such as InGaN to help with optical guiding of the mode. The InGaNlayer be comprised of 1 to 15% molar fraction of InN with a thicknessranging from 30 nm to about 250 nm and may be doped with an p-typespecies such as Mg. Overlying the active region and optional electronblocking layer and p-side waveguide layers is a p-cladding region and ap++ contact layer. The p-type cladding region is comprised of GaN,AlGaN, AlINGaN, or a combination thereof. The thickness of the p-typecladding layers is in the range of 0.3 μm to about 2 μm and is dopedwith Mg to a concentration of between 1×10¹⁶ cm⁻³ to 1×10¹⁹ cm⁻³. Aridge 211 is formed in the p-cladding region for lateral confinement inthe waveguide using an etching process selected from a dry etching or awet etching process. A dielectric material 213 such as silicon dioxideor silicon nitride or deposited on the surface region of the device andan opening is created on top of the ridge to expose a portion of the p++GaN layer. A p-contact 215 is deposited on the top of the device tocontact the exposed p++ contact region. The p-type contact may becomprised of a metal stack containing a of Au, Pd, Pt, Ni, Ti, or Ag andmay be deposited with electron beam deposition, sputter deposition, orthermal evaporation. A n-contact 201 is formed to the bottom of thesubstrate member. The n-type contact may be comprised of a metal stackcontaining Au, Al, Pd, Pt, Ni, Ti, or Ag and may be deposited withelectron beam deposition, sputter deposition, or thermal evaporation.

In multiple embodiments according to the present invention, the devicelayers comprise a super-luminescent light emitting diode or SLED. In allapplicable embodiments a SLED device can be interchanged with orcombined with laser diode devices according to the methods andarchitectures described in this invention. A SLED is in many wayssimilar to an edge emitting laser diode; however the emitting facet ofthe device is designed so as to have a very low reflectivity. A SLED issimilar to a laser diode as it is based on an electrically drivenjunction that when injected with current becomes optically active andgenerates amplified spontaneous emission (ASE) and gain over a widerange of wavelengths. When the optical output becomes dominated by ASEthere is a knee in the light output versus current (LI) characteristicwherein the unit of light output becomes drastically larger per unit ofinjected current. This knee in the LI curve resembles the threshold of alaser diode, but is much softer. A SLED would have a layer structureengineered to have a light emitting layer or layers clad above and belowwith material of lower optical index such that a laterally guidedoptical mode can be formed. The SLED would also be fabricated withfeatures providing lateral optical confinement. These lateralconfinement features may consist of an etched ridge, with air, vacuum,metal or dielectric material surrounding the ridge and providing a lowoptical-index cladding. The lateral confinement feature may also beprovided by shaping the electrical contacts such that injected currentis confined to a finite region in the device. In such a “gain guided”structure, dispersion in the optical index of the light emitting layerwith injected carrier density provides the optical-index contrast neededto provide lateral confinement of the optical mode.

SLEDs are designed to have high single pass gain or amplification forthe spontaneous emission generated along the waveguide. The SLED devicewould also be engineered to have a low internal loss, preferably below 1cm⁻¹, however SLEDs can operate with internal losses higher than this.In the ideal case, the emitting facet reflectivity would be zero,however in practical applications a reflectivity of zero is difficult toachieve and the emitting facet reflectivity is designs to be less than1%, less than 0.1%, less than 0.001%, or less than 0.0001% reflectivity.Reducing the emitting facet reflectivity reduces feedback into thedevice cavity, thereby increasing the injected current density at whichthe device will begin to lase. Very low reflectivity emitting facets canbe achieved by a combination of addition of anti-reflection coatings andby angling the emitting facet relative to the SLED cavity such that thesurface normal of the facet and the propagation direction of the guidedmodes are substantially non-parallel. In general, this would mean adeviation of more than 1-2 degrees. In practice, the ideal angle dependsin part on the anti-reflection coating used and the tilt angle must becarefully designed around a null in the reflectivity versus anglerelationship for optimum performance. Tilting of the facet with respectto the propagation direction of the guided modes can be done in anydirection relative to the direction of propagation of the guided modes,though some directions may be easier to fabricate depending on themethod of facet formation. Etched facets provide the most flexibilityfor facet angle determination. Alternatively, a very common method toachieve an angled output for reduced constructive interference in thecavity would to curve and/or angle the waveguide with respect to acleaved facet that forms on a pre-determined crystallographic plane inthe semiconductor chip. In this configuration the angle of lightpropagation is off-normal at a specified angle designed for lowreflectivity to the cleaved facet.

The spectra emitted by SLEDs differ from lasers in several ways. While aSLED device does produce optical gain in the laterally guided modes, thereduced optical feedback at the emitting facet results in a broader andmore continuous emission spectra. For example, in a Fabry-Perot (FP)laser, the reflection of light at the ends of the waveguide limits thewavelengths of light that can experience gain to those that result inconstructive interference, which is dependent on the length of thecavity. The spectra of a FP laser is thus a comb, with peaks and valleyscorresponding to the longitudinal modes and with an envelope defined bythe gain media and transverse modes supported by the cavity. Moreover,in a laser, feedback from emitting facet ensures that one of thetransverse modes will reach threshold at a finite current density. Whenthis happens, a subset of the longitudinal modes will dominate thespectra. In a SLED, the optical feedback is suppressed, which reducesthe peak to valley height of the comb in the gain spectra and alsopushes out thresholds to higher current densities. A SLED then will becharacterized by a relatively broad (>5 nm) and incoherent spectrum,which has advantages for spectroscopy, eye safety and reduced speckle.As an example, the well-known distortion pattern referred to as“speckle” is the result of an intensity pattern produced by the mutualinterference of a set of wavefronts on a surface or in a viewing plane.The general equations typically used to quantify the degree of speckleare inversely proportional to the spectral width.

It is also possible for the laser diode or SLED ridge, or in the case ofa gain-guided device the electrically injected region, would not be ofuniform width. The purpose of this would be to produce a wave-guide orcavity of larger width at one or both ends. This has two main advantagesover a ridge or injected region of uniform width. Firstly, the waveguidecan be shaped such that the resulting cavity can only sustain a singlelateral mode while allowing the total area of the device to besignificantly larger than that achievable in a device having a waveguideof uniform width. This increases the achievable optical power achievablein a device with a single lateral mode. Secondly, this allows for thecross-sectional area of the optical mode at the facets to besignificantly larger than in a single-mode device having a waveguide ofuniform width. Such a configuration reduces the optical power density ofthe device at the facet, and thereby reduces the likelihood thatoperation at high powers will result in optical damage to the facets.Single lateral mode devices may have some advantages in spectroscopy orin visible light communication where the single later mode results in asignificant reduction in spectral width relative to a multi-lateral modedevice with a wide ridge of uniform width. This would allow for morelaser devices of smaller differences in center wavelength to be includedin the same VLC emitter as the spectra would overlap less and be easierto demultiplex with filtered detectors. Optionally, both multi-mode andsingle-mode lasers would have significantly narrower spectra relative toLEDs with spectra of the same peak wavelength.

In an embodiment, the LD or SLED device is characterized by a ridge withnon-uniform width. The ridge is comprised by a first section of uniformwidth and a second section of varying width. The first section has alength between 100 and 500 μm long, though it may be longer. The firstsection has a width of between 1 and 2.5 μm, with a width preferablybetween 1 and 1.5 μm. The second section of the ridge has a first endand a second end. The first end connects with the first section of theridge and has the same width as the first section of the ridge. Thesecond end of the second section of the ridge is wider than the firstsection of the ridge, with a width between 5 and 50 μm and morepreferably with a width between 15 and 35 μm. The second section of theridge waveguide varies in width between its first and second endsmoothly. In some embodiments the second derivative of the ridge widthversus length is zero such that the taper of the ridge is linear. Insome embodiments, the second derivative is chosen to be positive ornegative. In general the rate of width increase is chosen such that theridge does not expand in width significantly faster than the opticalmode. In specific embodiments, the electrically injected area ispatterned such that only a part of the tapered portion of the waveguideis electrically injected.

In an embodiment, multiple laser dice emitting at different wavelengthsare transferred to the same carrier wafer in close proximity to oneanother; preferably within one millimeter of each other, more preferablywithin about 200 micrometers of each other and most preferably withinabout 50 μm of each other. The laser die wavelengths are chosen to beseparated in wavelength by at least twice the full width at half maximumof their spectra. For example, three dice, emitting at 440 nm, 450 nmand 460 nm, respectively, are transferred to a single carrier chip witha separation between die of less than 50 μm and die widths of less than50 μm such that the total lateral separation, center to center, of thelaser light emitted by the die is less than 200 μm. The closeness of thelaser die allows for their emission to be easily coupled into the sameoptical train or fiber optic waveguide or projected in the far fieldinto overlapping spots. In a sense, the lasers can be operatedeffectively as a single laser light source.

Such a configuration offers an advantage in that each individual laserlight source could be operated independently to convey information usingfor example frequency and phase modulation of an RF signal superimposedon DC offset. The time-averaged proportion of light from the differentsources could be adjusted by adjusting the DC offset of each signal. Ata receiver, the signals from the individual laser sources would bedemultiplexed by use of notch filters over individual photodetectorsthat filter out both the phosphor derived component of the white lightspectra as well as the pump light from all but one of the laser sources.Such a configuration would offer an advantage over an LED based visiblelight communication (VLC) source in that bandwidth would scale easilywith the number of laser emitters. Of course, a similar embodiment withsimilar advantages could be constructed from SLED emitters.

After the laser diode chip fabrication as described above, the laserdiode can be mounted to a submount. In some examples the submount iscomprised of AlN, SiC, BeO, diamond, or other materials such as metals,ceramics, or composites. The submount can be the common support memberwherein the phosphor member of the CPoS would also be attached.Alternatively, the submount can be an intermediate submount intended tobe mounted to the common support member wherein the phosphor material isattached. The submount member may be characterized by a width, length,and thickness. In an example wherein the submount is the common supportmember for the phosphor and the laser diode chip the submount would havea width and length ranging in dimension from about 0.5 mm to about 5 mmor to about 15 mm and a thickness ranging from about 150 μm to about 2mm. In the example wherein the submount is an intermediate submountbetween the laser diode chip and the common support member it could becharacterized by width and length ranging in dimension from about 0.5 mmto about 5 mm and the thickness may range from about 50 μm to about 500μm. The laser diode is attached to the submount using a bonding process,a soldering process, a gluing process, or a combination thereof. In oneembodiment the submount is electrically isolating and has metal bondpads deposited on top. The laser chip is mounted to at least one ofthose metal pads. The laser chip can be mounted in a p-side down or ap-side up configuration. After bonding the laser chip, wire bonds areformed from the chip to the submount such that the final chip onsubmount (CoS) is completed and ready for integration.

A schematic diagram illustrating a CoS based on a conventional laserdiode formed on gallium and nitrogen containing substrate technologyaccording to this present invention is shown in FIG. 5. The CoS iscomprised of submount material 301 configured to act as an intermediatematerial between a laser diode chip 302 and a final mounting surface.The submount is configured with electrodes 303 and 305 that may beformed with deposited metal layers such as Au. In one example, Ti/Pt/Auis used for the electrodes. Wirebonds 304 are configured to couple theelectrical power from the electrodes 303 and 305 on the submount to thelaser diode chip to generate a laser beam output 306 from the laserdiode. The electrodes 303 and 305 are configured for an electricalconnection to an external power source such as a laser driver, a currentsource, or a voltage source. Wirebonds 304 can be formed on theelectrodes to couple electrical power to the laser diode device andactivate the laser.

In another embodiment, the gallium and nitrogen containing laser diodefabrication includes an epitaxial release step to lift off theepitaxially grown gallium and nitrogen layers and prepare them fortransferring to a carrier wafer which could comprise the submount afterlaser fabrication. The transfer step requires precise placement of theepitaxial layers on the carrier wafer to enable subsequent processing ofthe epitaxial layers into laser diode devices. The attachment process tothe carrier wafer could include a wafer bonding step with a bondinterface comprised of metal-metal, semiconductor-semiconductor,glass-glass, dielectric-dielectric, or a combination thereof.

In yet another preferred variation of this CPoS white light source, aprocess for lifting-off gallium and nitrogen containing epitaxialmaterial and transferring it to the common support member can be used toattach the gallium and nitrogen containing laser epitaxial material to asubmount member. In this embodiment, the gallium and nitrogen epitaxialmaterial is released from the gallium and nitrogen containing substrateit was epitaxially grown on. As an example, the epitaxial material canbe released using a photoelectrochemical (PEC) etching technique. It isthen transferred to a submount material using techniques such as waferbonding wherein a bond interface is formed. For example, the bondinterface can be comprised of a Au—Au bond. The submount materialpreferably has a high thermal conductivity such as SiC, wherein theepitaxial material is subsequently processed to form a laser diode witha cavity member, front and back facets, and electrical contacts forinjecting current. After laser fabrication is complete, a phosphormaterial is introduced onto the submount to form an integrated whitelight source. The phosphor material may have an intermediate materialpositioned between the submount and the phosphor. The intermediatematerial may be comprised of a thermally conductive material such ascopper. The phosphor material can be attached to the submount usingconventional die attaching techniques using solders such as AuSn solder,but can be other techniques such as SAC solders such as SAC305, leadcontaining solder, or indium, but can be others. In an alternativeembodiment sintered Ag pastes or films can be used for the attachprocess at the interface. Sintered Ag attach material can be dispensedor deposited using standard processing equipment and cycle temperatureswith the added benefit of higher thermal conductivity and improvedelectrical conductivity. For example, AuSn has a thermal conductivity ofabout 50 W/m-K and electrical conductivity of about 16 μΩcm whereaspressureless sintered Ag can have a thermal conductivity of about 125W/m-K and electrical conductivity of about 4 μΩcm, or pressured sinteredAg can have a thermal conductivity of about 250 W/m-K and electricalconductivity of about 2.5 μΩcm. Due to the extreme change in melttemperature from paste to sintered form, (260 C.°-900°), processes canavoid thermal load restrictions on downstream processes, allowingcompleted devices to have very good and consistent bonds throughout.Optimizing the bond for the lowest thermal impedance is a key parameterfor heat dissipation from the phosphor, which is critical to preventphosphor degradation and thermal quenching of the phosphor material. Thebenefits of using this embodiment with lifted-off and transferredgallium and nitrogen containing material are the reduced cost, improvedlaser performance, and higher degree of flexibility for integrationusing this technology.

In this embodiment, gallium and nitrogen containing epitaxial layers aregrown on a bulk gallium and nitrogen containing substrate. The epitaxiallayer stack comprises at least a sacrificial release layer and the laserdiode device layers overlying the release layers. Following the growthof the epitaxial layers on the bulk gallium and nitrogen containingsubstrate, the semiconductor device layers are separated from thesubstrate by a selective wet etching process such as a PEC etchconfigured to selectively remove the sacrificial layers and enablerelease of the device layers to a carrier wafer. In one embodiment, abonding material is deposited on the surface overlying the semiconductordevice layers. A bonding material is also deposited either as a blanketcoating or patterned on the carrier wafer. Standard lithographicprocesses are used to selectively mask the semiconductor device layers.The wafer is then subjected to an etch process such as dry etch or wetetch processes to define via structures that expose the sacrificiallayers on the sidewall of the mesa structure. As used herein, the termmesa region or mesa is used to describe the patterned epitaxial materialon the gallium and nitrogen containing substrate and prepared fortransferring to the carrier wafer. The mesa region can be any shape orform including a rectangular shape, a square shape, a triangular shape,a circular shape, an elliptical shape, a polyhedron shape, or othershape. The term mesa shall not limit the scope of the present invention.

Following the definition of the mesa, a selective etch process isperformed to fully or partially remove the sacrificial layers whileleaving the semiconductor device layers intact. The resulting structurecomprises undercut mesas comprised of epitaxial device layers. Theundercut mesas correspond to dice from which semiconductor devices willbe formed on. In some embodiments a protective passivation layer can beemployed on the sidewall of the mesa regions to prevent the devicelayers from being exposed to the selective etch when the etchselectivity is not perfect. In other embodiments a protectivepassivation is not needed because the device layers are not sensitive tothe selective etch or measures are taken to prevent etching of sensitivelayers such as shorting the anode and cathode. The undercut mesascorresponding to device dice are then transferred to the carrier waferusing a bonding technique wherein the bonding material overlying thesemiconductor device layers is joined with the bonding material on thecarrier wafer. The resulting structure is a carrier wafer comprisinggallium and nitrogen containing epitaxial device layers overlying thebonding region.

In a preferred embodiment PEC etching is deployed as the selective etchto remove the a sacrificial layers. PEC is a photo-assisted wet etchtechnique that can be used to etch GaN and its alloys. The processinvolves an above-band-gap excitation source and an electrochemical cellformed by the semiconductor and the electrolyte solution. In this case,the exposed (Al,In,Ga)N material surface acts as the anode, while ametal pad deposited on the semiconductor acts as the cathode. Theabove-band-gap light source generates electron-hole pairs in thesemiconductor. Electrons are extracted from the semiconductor via thecathode while holes diffuse to the surface of material to form an oxide.Since the diffusion of holes to the surface requires the band bending atthe surface to favor a collection of holes, PEC etching typically worksonly for n-type material although some methods have been developed foretching p-type material. The oxide is then dissolved by the electrolyteresulting in wet etching of the semiconductor. Different types ofelectrolyte including HCl, KOH, and HNO₃ have been shown to be effectivein PEC etching of GaN and its alloys. The etch selectivity and etch ratecan be optimized by selecting a favorable electrolyte. It is alsopossible to generate an external bias between the semiconductor and thecathode to assist with the PEC etching process.

The preparation of the epitaxy wafer is shown in FIG. 6. A substrate 400is overlaid by a buffer layer 401, a selectively removable sacrificiallayer 407, another buffer layer 401, a collection of device layers 402and a contact layer 103. The sacrificial region is exposed by etching ofvias that extend below the sacrificial layer 407 and segment the layers401, 402, 403, and 407 into mesas. A layer composed of bonding media 408is deposited overlaying the mesas. In some embodiments the bonding layer408 is deposited before the sacrificial layer 407 is exposed. Finallythe sacrificial layer 407 is removed via a selective process. Thisprocess requires the inclusion of a buried sacrificial region, which canbe PEC etched selectively by bandgap. For GaN based semiconductordevices, InGaN layers such as quantum wells have been shown to be aneffective sacrificial region during PEC etching. The first step depictedin FIG. 6 is a top down etch to expose the sacrificial layers, followedby a bonding metal deposition as shown in FIG. 6. With the sacrificialregion exposed a bandgap selective PEC etch is used to undercut themesas. In one embodiment, the bandgaps of the sacrificial region and allother layers are chosen such that only the sacrificial region willabsorb light, and therefore etch, dining the PEC etch. Anotherembodiment of the invention involving light emitting devices uses asacrificial region with a higher bandgap than the active region suchthat both layers are absorbing during the bandgap PEC etching process.

Sacrificial layers for lift-off of the substrate via photochemicaletching would incorporate at a minimum a low-bandgap or doped layer thatwould absorb the pump light and have enhanced etch rate relative to thesurrounding material. The sacrificial layer 407 can be depositedepitaxially and their alloy composition and doping of these can beselected such that hole carrier lifetime and diffusion lengths are high.Defects that reduce hole carrier lifetimes and diffusion length must canbe avoided by growing the sacrificial layers under growth conditionsthat promote high material crystalline quality. An example of asacrificial layer would be InGaN layers that absorb at the wavelength ofan external light source. An etch stop layer designed with very low etchrate to control the thickness of the adjacent material remaining aftersubstrate removal can also be incorporated to allow better control ofthe etch process. The etch properties of the etch stop layer can becontrolled solely by or a combination of alloy composition and doping. Apotential etch stop layer would an AlGaN or GaN layer with a bandgaphigher than the external light source. Another potential etch stop layeris a highly doped n-type AlGaN or GaN layer with reduce minority carrierdiffusion lengths and lifetime thereby dramatically reducing the etchrate of the etch stop material.

In some embodiments PEC etching is achieved without the use of an activeregion protecting layer by electrically shorting the p-side of the laserdiode pn-junction to the n-side. Etching in the PEC process is achievedby the dissolution of AlInGaN materials at the wafer surface when holesare transferred to the etching solution. These holes are then recombinedin the solution with electrons extracted at the cathode metal interfacewith the etching solution. Charge neutrality is therefore achieved.Selective etching is achieved by electrically shorting the anode to thecathode. Electron hole pairs generated in the device light emittinglayers are swept out of the light emitting layers by the electric fieldof the of the p-n junction. Since holes are swept out of the activeregion, there is little or no etching of the light emitting layer. Thebuildup of carriers produces a potential difference that drives carriersthrough the metal interconnects that short the anode and cathode wherethey recombine. The flat band conditions in the sacrificial regionresult in a buildup of holes that result in rapid etching of thesacrificial layers. In one embodiment, the metal interconnects to shortthe anode and cathode can be used as anchor regions to mechanically holdthe gallium and nitrogen containing mesas in place prior to the bondingstep.

The relative etch rates of the sacrificial and active regions aredetermined by a number of factors, but primarily it is determined by thedensity of holes found in the active region at steady state. If themetal interconnects or anchors are very resistive, or if either thecathode or anode electrical contacts to the p-type and n-type,respectively, cladding regions are too resistive or have large Schottkybarriers then it is possible for carriers to accumulate on either sideof the p-n junction. These carriers will produce an electric field thatacts against the field in the depletion region and will reduce themagnitude of the field in the depletion region until the rate ofphoto-generated carrier drift out of the active region is balanced bythe recombination rate of carriers via the metal layers shorting thecathode and anode. Some recombination will take place via photochemicaletching, and since this scales with the density of holes in the activeregion it is preferable to prevent the buildup of a photo-induced biasacross the active region.

In one embodiment thermocompression bonding is used to transfer thegallium and nitrogen epitaxial semiconductor layers to the carrierwafer. In this embodiment thermocompression bonding involves bonding ofthe epitaxial semiconductor layers to the carrier wafer at elevatedtemperatures and pressures using a bonding media 408 disposed betweenthe epitaxial layers and handle wafer. The bonding media 408 may becomprised of a number of different layers, but typically contain atleast one layer (the bonding layer 408) that is composed of a relativelyductile material with a high surface diffusion rate. In many cases thismaterial is comprised of Au, Al or Cu. The bonding media 408 may alsoinclude layers disposed between the bonding layer and the epitaxialmaterials or handle wafer that promote adhesion. For example an Aubonding layer on a Si wafer may result in diffusion of Si to the bondinginterface, which would reduce the bonding strength. Inclusion of adiffusion barrier such as silicon oxide or nitride would limit thiseffect. Relatively thin layers of a second material may be applied onthe top surface of the bonding layer in order to promote adhesionbetween the bonding layers disposed on the epitaxial material andhandle. Some bonding layer materials of lower ductility than gold (e.g.Al, Cu etc.) or which are deposited in a way that results in a roughfilm (for example electrolytic deposition) may require planarization orreduction in roughness via chemical or mechanical polishing beforebonding, and reactive metals may require special cleaning steps toremove oxides or organic materials that may interfere with bonding.

Thermocompressive bonding can be achieved at relatively lowtemperatures, typically below 500 C.° and above 200 C°. Temperaturesshould be high enough to promote diffusivity between the bonding layersat the bonding interface, but not so high as to promote unintentionalalloying of individual layers in each metal stack. Application ofpressure enhances the bond rate, and leads to some elastic and plasticdeformation of the metal stacks that brings them into better and moreuniform contact. Optimal bond temperature, time and pressure will dependon the particular bond material, the roughness of the surfaces formingthe bonding interface and the susceptibility to fracture of the handlewafer or damage to the device layers under load.

The bonding interface need not be composed of the totality of the wafersurface. For example, rather than a blanket deposition of bonding metal,a lithographic process could be used to deposit metal in discontinuousareas separated by regions with no bonding metal. This may beadvantageous in instances where defined regions of weak or no bondingaid later processing steps, or where an air gap is needed. One exampleof this would be in removal of the GaN substrate using wet etching of anepitaxially grown sacrificial layer. To access the sacrificial layer onemust etch vias into either of the two surfaces of the epitaxial wafer,and preserving the wafer for re-use is most easily done if the vias areetched from the bonded side of the wafer. Once bonded, the etched viasresult in channels that can conduct etching solution from the edges tothe center of the bonded wafers, and therefore the areas of thesubstrate comprising the vias are not in intimate contact with thehandle wafer such that a bond would form.

The bonding media can also be an amorphous or glassy material bondedeither in a reflow process or anodically. In anodic bonding the media isa glass with high ion content where mass transport of material isfacilitated by the application of a large electric field. In reflowbonding the glass has a low melting point, and will form contact and agood bond under moderate pressures and temperatures. All glass bonds arerelatively brittle, and require the coefficient of thermal expansion ofthe glass to be sufficiently close to the bonding partner wafers (i.e.the GaN wafer and the handle). Glasses in both cases could be depositedvia vapor deposition or with a process involving spin on glass. In bothcases the bonding areas could be limited in extent and with geometrydefined by lithography or silk-screening process.

Gold-gold metallic bonding is used as an example in this work, althougha wide variety of oxide bonds, polymer bonds, wax bonds, etc., arepotentially suitable. Submicron alignment tolerances are possible usingcommercial available die bonding equipment. In another embodiment of theinvention the bonding layers can be a variety of bonding pairs includingmetal-metal, oxide-oxide, soldering alloys, photoresists, polymers, wax,etc. Only epitaxial die which are in contact with a bond bad on thecarrier wafer will bond. Sub-micron alignment tolerances are possible oncommercially available die or flip chip bonders.

In an example, an oxide is overlaid on an exposed planar n-type orp-type gallium and nitrogen containing material or over an exposedplanar n-type or p-type gallium and nitrogen containing material usingdirect wafer bonding of the surface of the gallium and nitrogencontaining material to the surface of a carrier wafer comprisedprimarily of an oxide or a carrier wafer with oxide layers disposed onthem. In both cases the oxide surface on the carrier wafer and theexposed gallium and nitrogen containing material are cleaned to reducethe amount of hydrocarbons, metal ions and other contaminants on thebonding surfaces. The bonding surfaces are then brought into contact andbonded at elevated temperature under applied pressure. In some cases thesurfaces are treated chemically with acids, bases or plasma treatmentsto produce a surface that yields a weak bond when brought into contactwith the oxide surface. For example the exposed surface of the galliumcontaining material may be treated to form a thin layer of galliumoxide, which being chemically similar to the oxide bonding surface willbond more readily. Furthermore the oxide and now gallium oxideterminated surface of the gallium and nitrogen containing material maybe treated chemically to encourage the formation of dangling hydroxylgroups (among other chemical species) that will form temporary or weakchemical or van der Waals bonds when the surfaces are brought intocontact, which are subsequently made permanent when treated at elevatedtemperatures and elevated pressures.

In an alternative example, an oxide material is deposited overlying thedevice layer mesa region to form a bond region. The carrier wafer isalso prepared with an oxide layer to form a bond region. The oxide layeroverlying the carrier wafer could be patterned or could be a blanketlayer. The oxide surface on the carrier wafer and the oxide surfaceoverlying the mesa device layer mesa regions are cleaned to reduce theamount of hydrocarbons, metal ions and other contaminants on the bondingsurfaces. The bonding surfaces are then brought into contact and bondedat elevated temperature under applied pressure. In one embodiment, achemical mechanical polish (CMP) process is used to planarize the oxidesurface and make them smooth to improve the resulting bond. In somecases the surfaces are treated chemically with acids, bases or plasmatreatments to produce a surface that yields a weak bond when broughtinto contact with the oxide surface. Bonding is performed at elevatedtemperatures and elevated pressures.

In another embodiment the bonding media could be a dielectric materialsuch as silicon dioxide or silicon nitride. Such a bonding media may bedesirable where low conductivity is desired at the bond interface toachieve properties such as reduced device capacitance to enableincreased frequency operation. The bond media comprising the bondinterface can be comprised of many other materials such as oxide-oxidepair, semiconductor-semiconductor pair, spin-on-glass, soldering alloys,polymers, photoresists, wax, or a combination thereof.

The carrier wafer can be chosen based on any number of criteriaincluding but not limited to cost, thermal conductivity, thermalexpansion coefficients, size, electrical conductivity, opticalproperties, and processing compatibility. The patterned epitaxy wafer,or donor, is prepared in such a way as to allow subsequent selectiverelease of bonded epitaxy regions, here-in referred to as die. Thepatterned carrier wafer is prepared such that bond pads are arranged inorder to enable the selective area bonding process. The bonding materialcan be a variety of media including but not limited to metals, polymers,waxes, and oxides. These wafers can be prepared by a variety of processflows, some embodiments of which are described below. In the firstselective area bond step, the epitaxy wafer is aligned with thepre-patterned bonding pads on the carrier wafer and a combination ofpressure, heat, and/or sonication is used to bond the mesas to thebonding pads.

In some embodiments of the invention the carrier wafer is anothersemiconductor material, a metallic material, or a ceramic material. Somepotential candidates include silicon, gallium arsenide, sapphire,silicon carbide, diamond, gallium nitride, AlN, polycrystalline AlN,indium phosphide, germanium, quartz, copper, copper tungsten, gold,silver, aluminum, stainless steel, or steel.

In some embodiments, the carrier wafer is selected based on size andcost. For example, ingle crystal silicon wafers are available indiameters up to 300 ram or 12 inch, and are most cost effective. Bytransferring gallium and nitrogen epitaxial materials from 2″ galliumand nitrogen containing bulk substrates to large silicon substrates of150 mm, 200 mm, or 300 mm diameter the effective area of thesemiconductor device wafer can be increases by factors of up to 36 orgreater. This feature of this invention allows for high quality galliumand nitrogen containing semiconductor devices to be fabricated in massvolume leveraging the established infrastructure in silicon foundries.

In some embodiments of the invention, the carrier wafer material ischosen such that it has similar thermal expansion properties togroup-III nitrides, high thermal conductivity, and is available as largearea wafers compatible with standard semiconductor device fabricationprocesses. The carrier wafer is then processed with structures enablingit to also act as the submount for the semiconductor devices.Singulation of the carrier wafers into individual die can beaccomplished either by sawing, cleaving, or a scribing and breakingprocess. By combining the functions of the carrier wafer and finishedsemiconductor device submount the number of components and operationsneeded to build a packaged device is reduced, thereby lowering the costof the final semiconductor device significantly.

In an example, the carrier wafer is a solid material with thermalconductivity greater than 100 W/m-K. In an example, the common substrateis preferably a solid material with thermal conductivity greater than200 W/m-K. In an example, the common substrate is preferably a solidmaterial with thermal conductivity greater than 400 W/m-K. In anexample, the common substrate is preferably a solid material withelectrical insulator with electrical resistivity greater than 1×10⁶ohm-cm. In an example, the common substrate is preferably a solidmaterial with thin film material providing electrical 1×10⁶ ohm-cm. Inan example, the common substrate selected from one or more of Al₂O₃,AlN, SiC, BeO and diamond. In an example, the common substrate ispreferably comprised of crystalline SiC. In an example, the commonsubstrate is preferably comprised of crystalline SiC with a thin film ofSi₃N₄ deposited onto the top surface. In an example, the commonsubstrate contains metal traces providing electrically conductiveconnections between the one or more low-cost laser diodes. In anexample, the common substrate contains metal traces providing thermallyconductive connections between the one or more low-cost laser diodes andthe common substrate.

In one embodiment of this invention, the bonding of the semiconductordevice epitaxial material to the carrier wafer process can be performedprior to the selective etching of the sacrificial region and subsequentrelease of the gallium and nitrogen containing substrate. FIG. 7 is aschematic illustration of a process comprised of first forming the bondbetween the gallium and nitrogen containing epitaxial material formed onthe gallium and nitrogen containing substrate and then subjecting asacrificial release material to the PEC etch process to release thegallium and nitrogen containing substrate. In this embodiment, anepitaxial material is deposited on the gallium and nitrogen containingsubstrate, such as a GaN substrate, through an epitaxial depositionprocess such as metal organic chemical vapor deposition (MOCVD),molecular beam epitaxy (MBE), or other. The epitaxial material includesat least a sacrificial release layer and a device layers. In someembodiments a buffer layer is grown on between the substrate surfaceregion and the sacrificial release region. Referring to FIG. 7,substrate wafer 500 is overlaid by a buffer layer 502, a selectivelyetchable sacrificial layer 504 and a collection of device layers 501.The bond layer 505 is deposited along with a cathode metal 506 that willbe used to facilitate the photoelectrochemical etch process forselectively removing the sacrificial layer 504.

In a preferred embodiment of this invention, the bonding process isperformed after the selective etching of the sacrificial region. Thisembodiment offers several advantages. One advantage is easier access forthe selective etchant to uniformly etch the sacrificial region acrossthe semiconductor wafer comprising a bulk gallium and nitrogencontaining substrate such as GaN and bulk gallium and nitrogencontaining epitaxial device layers. A second advantage is the ability toperform multiple bond steps. In one example, the “etch-then-bond”process flow can be deployed where the mesas are retained on thesubstrate by controlling the etch process such that not all parts of thesacrificial layer is removed. Referring to FIG. 7, a substrate wafer 500is overlaid by a buffer layer 502, a selectively etchable sacrificiallayer 504 and a collection of device layers 501. A bond layer 505 isdeposited along with a cathode metal 506 that will be used to facilitatethe photoelectrochemical etch process for selectively removing thesacrificial layer 504. The selective etch process is carried out to thepoint where only a small fraction of the sacrificial layer 504 isremaining, such that multiple mesas or mesa regions are formed andretained on the substrate, but the unetched portions of the sacrificiallayer 504 are easily broken during or after the mesas are bonded to acarrier wafer 508.

A critical challenge of the etch-then-bond embodiment is mechanicallysupporting the undercut epitaxial device layer mesa region fromspatially shifting prior to the bonding step. If the mesas shift theability to accurately align and arrange them to the carrier wafer willbe compromised, and hence the ability to manufacture with acceptableyields. This challenge mechanically fixing the mesa regions in placeprior to bonding can be achieved in several ways. In a preferredembodiment anchor regions 503 are used to mechanically support the mesasto the gallium and nitrogen containing substrate prior to the bondingstep wherein they are releases from the gallium and nitrogen containingsubstrate 500 and transferred to the carrier wafer 508.

Anchor regions are special features that can be designed into the photomasks which attach the undercut device layers 501 to the buffer layer502 of the gallium and nitrogen containing substrate 500, but which aretoo large to themselves be undercut, or which due to the design of themask contain regions 503 where the sacrificial layers 504 are notremoved or these features may be composed of metals or dielectrics thatare resistant to the etch. These features act as anchors, preventing theundercut device layers 501 from detaching from the substrate 500 andprevent the device layers 501 from spatially shifting. This anchorattachment to the substrate can also be achieved by incompletelyremoving the sacrificial layer 504, such that there is a tenuousconnection between the undercut device layers 501 and the substratewhich can be broken during bonding. The surfaces of the bonding material507 on the carrier wafer 508 and the device wafer 500 are then broughtinto contact and a bond is formed which is stronger than the attachmentof the undercut device layers 501 to the material in the anchor regions503 of the sacrificial layers 504. After bonding, the separation of thecarrier wafer 508 and device wafer 500 transfers the device layers 501to the carrier wafer 508.

Other than typical GaN based laser devices, undercut AlInGaAsP basedlaser devices can be produced in a manner similar to GaN based laserdiodes described in this invention. There are a number of wet etchesthat etch some AlInGaAsP alloys selectively. In one embodiment, anAlGaAs or AlGaP sacrificial layer could be grown clad with GaAs etchstop layers. When the composition of Al_(x)Ga_(1-x)As andAl_(x)Ga_(1-x)P is high (x>0.5) AlGaAs can be etched with almostcomplete selectivity (i.e. etch rate of AlGaAs>10⁶ times that of GaAs)when etched with HF. InGaP and AlInP with high InP and AlP compositionscan be etched with HCl selectively relative to GaAs. GaAs can be etchedselectively relative to AlGaAs using C₆H₈O₇:H₂O₂:H₂O. There are a numberof other combinations of sacrificial layer, etch-stop layer and etchchemistry which are widely known to those knowledgeable in the art ofmicromachining AlInGaAsP alloys.

In an embodiment, the AlInGaAsP device layers are exposed to the etchsolution which is chosen along with the sacrificial layer compositionsuch that only the sacrificial layers experience significant etching.The active region can be prevented from etching during thecompositionally selective etch using an etch resistant protective layer,such as like silicon dioxide, silicon nitride, metals or photoresistamong others, on the sidewall. This step is followed by the depositionof a protective insulating layer on the mesa sidewalls, which serves toblock etching of the active region during the later sacrificial regionundercut etching step. A second top down etch is then performed toexpose the sacrificial layers and bonding metal is deposited. With thesacrificial region exposed a compositionally selective etch is used toundercut the mesas. At this point, the selective area bonding process isused to continue fabricating devices. The device layers should beseparated from the sacrificial layers by a layer of material that isresistant to etching. This is to prevent etching into the device layersafter partially removing the sacrificial layers.

In one embodiment the anchor region is formed by features that are widerthan the device layer mesas such that the sacrificial region in theseanchor regions is not fully removed during the undercut of the devicelayers. In one example the mesas are retained on the substrate bydeposition of an etch-resistant material acting as an anchor byconnecting the mesas to the substrate. In this example a substrate waferis overlaid by a buffer layer, a selectively etchable sacrificial layerand a collection of device layers. The bond layer is deposited alongwith a cathode metal that will be used to facilitate thephotoelectrochemical etch process for selectively removing thesacrificial layer. A layer of etch resistant material, which may becomposed of metal, ceramic, polymer or a glass, is deposited such thatit connects to both the mesa and the substrate. The selective etchprocess is carried out such that the sacrificial layer is fully removedand only the etch-resistant layer connects the mesa to the substrate.

In another example of anchor techniques, the mesas are retained on thesubstrate by use of an anchor composed of epitaxial material. In thisexample a substrate wafer is overlaid by a buffer layer, a selectivelyetchable sacrificial layer and a collection of device layers. The bondlayer is deposited along with a cathode metal that will be used tofacilitate the photoelectrochemical etch process for selectivelyremoving the sacrificial layer. The anchor is shaped such that duringthe etch, a small portion of the sacrificial layer remains unetched andcreates a connection between the undercut mesa and the substrate wafer.

In one embodiment the anchors are positioned either at the ends or sidesof the undercut die such that they are connected by a narrow undercutregion of material. In this example the narrow connecting material isfar from the bond metal and is design such that the undercut materialcleaves at the connecting material rather than across the die. This hasthe advantage of keeping the entire width of the die undamaged, whichwould be advantageous. In another embodiment, geometric features areadded to the connecting material to act as stress concentrators and thebond metal is extended onto the narrow connecting material. The bondmetal reinforces the bulk of the connecting material. Adding thesefeatures increases the control over where the connection will cleave.These features can be triangles, circles, rectangles or any deviationthat provides a narrowing of the connecting material or a concaveprofile to the edge of the connecting material.

In another embodiment the anchors are of small enough lateral extentthat they may be undercut, however a protective coating is used toprevent etch solution from accessing the sacrificial layers in theanchors. This embodiment is advantageous in cases when the width of thedie to be transferred is large. Unprotected anchors would need to belarger to prevent complete undercutting, which would reduce the densityof die and reduce the utilization efficiency of epitaxial material.

In another embodiment, the anchors are located at the ends of the dieand the anchors form a continuous strip of material that connects to allor a plurality of die. This configuration is advantageous since theanchors can be patterned into the material near the edge of wafers orlithographic masks where material utilization is otherwise poor. Thisallows for utilization of device material at the center of the patternto remain high even when die sizes become large.

In a preferred embodiment the anchors are formed by depositing separateregions of an etch-resistant material that adheres well to the epitaxialand substrate material. These regions overlay a portion of thesemiconductor device layer mesa and some portion of the structure, suchas the substrate, that will not be undercut during the etch. Theseregions form a continuous connection, such that after the semiconductordevice layer mesa is completely undercut they provide a mechanicalsupport preventing the semiconductor device layer mesa from detachingfrom the substrate. Metal layers are then deposited on the top ofsemiconductor device layer mesa, the sidewall of the semiconductordevice layer mesa and the bottom of the etched region surrounding themesa such that a continuous connection is formed. As an example, themetal layers could comprise about 20 nm of titanium to provide goodadhesion and be capped with about 500 nm of gold, but of course thechoice of metal and the thicknesses could be others. In an example, thelength of the semiconductor device die sidewall coated in metal is about1 nm to about 40 nm, with the upper thickness being less than the widthof the semiconductor device die such that the sacrificial layer isetched completely in the region near the metal anchor where access tothe sacrificial layer by etchant will be limited.

The mesa regions can be formed by dry or wet chemical etching, and inone example would include at least a p++ GaN contact layer, a p-typecladding layer comprised of GaN, AlGaN, or InAlGaN, light emittinglayers such as quantum wells separated by barriers, waveguiding layerssuch as InGaN layers, and the a n-type cladding layers comprised of GaN,AlGaN, or InAlGaN, the sacrificial layer (504), and a portion of then-type GaN epitaxial layer beneath the sacrificial layer. A p-contactmetal is first deposited on the p++ GaN contact layer in order to form ahigh quality electrical contact with the p-type cladding. A second metalstack is then patterned and deposited on the mesa, overlaying thep-contact metal. The second metal stack consists of an n-contact metal,forming a good electrical contact with the n-type GaN layer beneath thesacrificial layer, as well as a relatively thick metal layer that actsas both the mesa bond pad 505 and the cathode metal stack 506. Thebond/cathode metal also forms a thick layer overlaying the edge of themesa and providing a continuous connection between the mesa top and thesubstrate. After the sacrificial layer 504 is removed by selectivephotochemical etching the thick metal provides mechanical support toretain the mesa in position on the GaN wafer until the bonding to (thebond material 507 of) the carrier wafer 508 is carried out.

The use of metal anchors have several advantages over the use of anchorsmade from the epitaxial device material. The first is density of thetransferrable mesas on the donor wafer (500) containing the epitaxialsemiconductor device layers and the gallium and nitrogen containing bulksubstrate. Anchors made from the epitaxial material must be large enoughto not be fully undercut by the selective etch, or they must beprotected somehow with a passivation layer. The inclusion of a largefeature that is not transferred will reduce the density of mesas in twodimensions on the epitaxial device wafer. The use of metal anchors ispreferable because the anchors are made from a material that isresistant to etch and therefore can be made with small dimensions thatdo not impact mesa density. The second advantage is that it simplifiesthe processing of the mesas because a separate passivation layer is nolonger needed to isolate the active region from the etch solution.Removing the active region protecting layer reduces the number offabrication steps while also reducing the size of the mesa required.

In a particular embodiment, the cathode metal stack 506 also includesmetal layers intended to increase the strength of the metal anchors. Forexample the cathode metal stack might consist of 100 nm of Ti to promoteadhesion of the cathode metal stack and provide a good electricalcontact to the n-type cladding. The cathode metal stack 506 could thenincorporate a layer of tungsten, which has an elastic modulus on theorder of four times higher than gold. Incorporating the tungsten wouldreduce the thickness of gold required to provide enough mechanicalsupport to retain the mesas after they are undercut by the selectiveetch.

In another embodiment of the invention the sacrificial region iscompletely removed by PEC etching and the mesa remains anchored in placeby any remaining defect pillars. PEC etching is known to leave intactmaterial around defects which act as recombination centers. Additionalmechanisms by which a mesa could remain in place after a completesacrificial etch include static forces or Van der Waals forces. In oneembodiment the undercutting process is controlled such that thesacrificial layer is not fully removed.

In a preferred embodiment, the semiconductor device epitaxy materialwith the underlying sacrificial region is fabricated into a dense arrayof mesas on the gallium and nitrogen containing bulk substrate with theoverlying semiconductor device layers. The mesas are formed using apatterning and a wet or dry etching process wherein the patterningcomprises a lithography step to define the size and pitch of the mesaregions. Dry etching techniques such as reactive ion etching,inductively coupled plasma etching, or chemical assisted ion beametching are candidate methods. Alternatively, a wet etch can be used.The etch is configured to terminate at or below the a sacrificial regionbelow the device layers. This is followed by a selective etch processsuch as PEC to fully or partially etch the exposed sacrificial regionsuch that the mesas are undercut. This undercut mesa pattern pitch willbe referred to as the ‘first pitch’. The first pitch is often a designwidth that is suitable for fabricating each of the epitaxial regions onthe substrate, while not large enough for the desired completedsemiconductor device design, which often desire larger non-activeregions or regions for contacts and the like. For example, these mesaswould have a first pitch ranging from about 5 μm to about 500 μm or toabout 5000 μm. Each of these mesas is a ‘die’.

In a preferred embodiment, these dice are transferred to a carrier waferat a second pitch using a selective bonding process such that the secondpitch on the carrier wafer is greater than the first pitch on thegallium and nitrogen containing substrate. In this embodiment the diceare on an expanded pitch for so called “die expansion”. In an example,the second pitch is configured with the dice to allow each die with aportion of the carrier wafer to be a semiconductor device, includingcontacts and other components. For example, the second pitch would beabout 50 μm to about 1000 μm or to about 5000 μm, but could be as largeat about 3-10 mm or greater in the case where a large semiconductordevice chip is required for the application. The larger second pitchcould enable easier mechanical handling without the expense of thecostly gallium and nitrogen containing substrate and epitaxial material,allow the real estate for additional features to be added to thesemiconductor device chip such as bond pads that do not require thecostly gallium and nitrogen containing substrate and epitaxial material,and/or allow a smaller gallium and nitrogen containing epitaxial wafercontaining epitaxial layers to populate a much larger carrier wafer forsubsequent processing for reduced processing cost. For example, a 4 to 1die expansion ratio would reduce the density of the gallium and nitrogencontaining material by a factor of 4, and hence populate an area on thecarrier wafer 4 times larger than the gallium and nitrogen containingsubstrate. This would be equivalent to turning a 2″ gallium and nitrogensubstrate into a 4″ carrier wafer. In particular, the present inventionincreases utilization of substrate wafers and epitaxy material through aselective area bonding process to transfer individual die of epitaxymaterial to a carrier wafer in such a way that the die pitch isincreased on the carrier wafer relative to the original epitaxy wafer.The arrangement of epitaxy material allows device components which donot require the presence of the expensive gallium and nitrogencontaining substrate and overlying epitaxy material often fabricated ona gallium and nitrogen containing substrate to be fabricated on thelower cost carrier wafer, allowing for more efficient utilization of thegallium and nitrogen containing substrate and overlying epitaxymaterial.

FIG. 8 is a schematic representation of the die expansion process withselective area bonding according to the present invention. A devicewafer is prepared for bonding in accordance with an embodiment of thisinvention. The device wafer consists of a substrate 606, buffer layers603, a fully removed sacrificial layer 609, device layers 602, bondingmedia 601, cathode metal 605, and an anchor material 604. Thesacrificial layer 609 is removed in the PEC etch with the anchormaterial 604 is retained. The mesa regions formed in the gallium andnitrogen containing epitaxial wafer form dice of epitaxial material andrelease layers defined through processing. Individual epitaxial materialdie are formed at first pitch. A carrier wafer is prepared consisting ofthe carrier wafer substrate 607 and bond pads 608 at second pitch. Thesubstrate 606 is aligned to the carrier wafer 607 such that a subset ofthe mesa on the gallium and nitrogen containing substrate 606 with afirst pitch aligns with a subset of bond pads 608 on the carrier wafer607 at a second pitch. Since the first pitch is greater than the secondpitch and the mesas will comprise device die, the basis for dieexpansion is established. The bonding process is carried out and uponseparation of the substrate from the carrier wafer 607 the subset ofmesas on the substrate 606 are selectively transferred to the carrierwafer 607. The process is then repeated with a second set of mesas andbond pads 608 on the carrier wafer 607 until the carrier wafer 607 ispopulated fully by epitaxial mesas. The gallium and nitrogen containingepitaxy substrate 201 can now optionally be prepared for reuse.

In the example depicted in FIG. 8, one quarter of the epitaxial dice onthe epitaxy wafer 606 are transferred in this first selective bond step,leaving three quarters on the epitaxy wafer 606. The selective areabonding step is then repeated to transfer the second quarter, thirdquarter, and fourth quarter of the epitaxial die to the patternedcarrier wafer 607. This selective area bond may be repeated any numberof times and is not limited to the four steps depicted in FIG. 8. Theresult is an array of epitaxial die on the carrier wafer 607 with awider die pitch than the original die pitch on the epitaxy wafer 606.The die pitch on the epitaxial wafer 606 will be referred to as pitch 1,and the die pitch on the carrier wafer 607 will be referred to as pitch2, where pitch 2 is greater than pitch 1.

In one embodiment the bonding between the carrier wafer and the galliumand nitrogen containing substrate with epitaxial layers is performedbetween bonding layers that have been applied to the carrier and thegallium and nitrogen containing substrate with epitaxial layers. Thebonding layers can be a variety of bonding pairs including metal-metal,oxide-oxide, soldering alloys, photoresists, polymers, wax, etc. Onlyepitaxial dice which are in contact with a bond bad 608 on the carrierwafer 607 will bond. Sub-micron alignment tolerances are possible oncommercial die bonders. The epitaxy wafer 606 is then pulled away,breaking the epitaxy material at a weakened epitaxial release layer 609such that the desired epitaxial layers remain on the carrier wafer 607.Herein, a ‘selective area bonding step’ is defined as a single iterationof this process.

In one embodiment, the carrier wafer 607 is patterned in such a way thatonly selected mesas come in contact with the metallic bond pads 608 onthe carrier wafer 607. When the epitaxy substrate 606 is pulled away thebonded mesas break off at the weakened sacrificial region, while theun-bonded mesas remain attached to the epitaxy substrate 606. Thisselective area bonding process can then be repeated to transfer theremaining mesas in the desired configuration. This process can berepeated through any number of iterations and is not limited to the twoiterations depicted in FIG. 8. The carrier wafer can be of any size,including but not limited to about 2 inch, 3 inch, 4 inch, 6 inch, 8inch, and 12 inch. After all desired mesas have been transferred, asecond bandgap selective PEC etching can be optionally used to removeany remaining sacrificial region material to yield smooth surfaces. Atthis point standard semiconductor device processes can be carried out onthe carrier wafer. Another embodiment of the invention incorporates thefabrication of device components on the dense epitaxy wafers before theselective area bonding steps.

In an example, the present invention provides a method for increasingthe number of gallium and nitrogen containing semiconductor deviceswhich can be fabricated from a given epitaxial surface area; where thegallium and nitrogen containing epitaxial layers overlay gallium andnitrogen containing substrates. The gallium and nitrogen containingepitaxial material is patterned into die with a first die pitch; the diefrom the gallium and nitrogen containing epitaxial material with a firstpitch is transferred to a carrier wafer to form a second die pitch onthe carrier wafer; the second die pitch is larger than the first diepitch.

In an example, each epitaxial device die is an etched mesa with a pitchof between about 1 μm and about 100 μm wide or between about 100 μm andabout 500 μm wide or between about 500 μm and about 3000 μm wide andbetween about 100 and about 3000 μm long. In an example, the second diepitch on the carrier wafer is between about 100 μm and about 200 μm orbetween about 200 μm and about 1000 μm or between about 1000 μm andabout 3000 μm. In an example, the second die pitch on the carrier waferis between about 2 times and about 50 times larger than the die pitch onthe epitaxy wafer. In an example, semiconductor LED devices, laserdevices, or electronic devices are fabricated on the carrier wafer afterepitaxial transfer. In an example, the semiconductor devices containGaN, AlN, InN, InGaN, AlGaN, InAlN, and/or InAlGaN. In an example, thegallium and nitrogen containing material are grown on a polar, nonpolar,or semipolar plane. In an example, one or multiple semiconductor devicesare fabricated on each die of epitaxial material. In an example, devicecomponents which do not require epitaxy material are placed in the spacebetween epitaxy die.

In one embodiment, device dice are transferred to a carrier wafer suchthat the distance between die is expanded in both the transverse as wellas lateral directions. This can be achieved by spacing bond pads on thecarrier wafer with larger pitches than the spacing of device die on thesubstrate.

In another embodiment of the invention device dice from a plurality ofepitaxial wafers are transferred to the carrier wafer such that eachdesign width on the carrier wafer contains dice from a plurality ofepitaxial wafers. When transferring dice at close spacing from multipleepitaxial wafers, it is important for the un-transferred dice on theepitaxial wafer to not inadvertently contact and bond to die alreadytransferred to the carrier wafer. To achieve this, epitaxial dice from afirst epitaxial wafer are transferred to a carrier wafer using themethods described above. A second set of bond pads are then deposited onthe carrier wafer and are made with a thickness such that the bondingsurface of the second pads is higher than the top surface of the firstset of transferred die. This is done to provide adequate clearance forbonding of the dice from the second epitaxial wafer. A second epitaxialwafer transfers a second set of dice to the carrier wafer. Finally, thesemiconductor devices are fabricated and passivation layers aredeposited followed by electrical contact layers that allow each die tobe individually driven. The dice transferred from the first and secondsubstrates are spaced at a pitch which is smaller than the second pitchof the carrier wafer. This process can be extended to transfer of dicefrom any number of epitaxial substrates, and to transfer of any numberof devices per dice from each epitaxial substrate.

An example of an epitaxial structure for a laser diode device accordingto this invention is shown in FIG. 9. In this embodiment, an n-GaNbuffer layer followed by a sacrificial layer is grown along with ann-contact layer that will be exposed after transfer. Overlaying then-contact layer are n-cladding layers, an n-side separate confinementheterostructure (n-SCH) layer, an active region, a p-side separateconfinement heterostructure (p-SCH) layer, a p-cladding layer, and ap-contact region. In one example of this embodiment an n-type GaN bufferlayer is grown on a c-plane oriented, bulk-GaN wafer. In another examplethe substrate is comprised of a semipolar or nonpolar orientation.Overlaying the buffer layer is a sacrificial layer comprised by InGaNwells separated by GaN barriers with the well composition and thicknesschosen to result in the wells absorbing light at wavelengths shorterthan 450 nm, though in some embodiments the absorption edge would be asshort as 400 nm and in other embodiments as long as 520 nm. Overlayingthe sacrificial layer is an n-type contact layer consisting of GaN dopedwith silicon at a concentration of 5×10¹⁸ cm⁻³, but can be other dopinglevels in the range between 5×10¹⁷ and 1×10¹⁹ cm⁻³. Overlaying thecontact layer is an n-type cladding layer comprised of GaN or AlGaNlayer with a thickness of 1 micron with an average composition of 4%AlN, though in other embodiments the thickness may range from 0.25 to 2μm with an average composition of 0-8% AlN. Overlaying the n-cladding isan n-type wave-guiding or separate confinement heterostructure (SCH)layer that helps provide index contrast with the cladding to improveconfinement of the optical modes. The nSCH is InGaN with a compositionof 4% InN and has a thickness of 100 nm, though in other embodiments theInGaN nSCH may range from 20 to 300 nm in thickness and from 0-8% InNand may be composed of several layers of varying composition andthickness. Overlaying the n-SCH are light emitting quantum well layersconsisting of two 3.5 nm thick In_(0.15)Ga_(0.85)N quantum wellsseparated by 4 nm thick GaN barriers, though in other embodiments theremay 1 to 7 light emitting quantum well layers consisting of 1 nm to 6 nmthick quantum wells separated by GaN or InGaN barriers of 1 nm to 25 nmthick. Overlaying the light emitting layers is an optional InGaN pSCHwith a composition of 4% InN and has a thickness of 100 nm, though inother embodiments the nSCH may range from 20 to 300 nm in thickness andfrom 0-8% InN and may be composed of several layers of varyingcomposition and thickness. Overlaying the pSCH is an optional AlGaNelectron blocking layer (EBL) with a composition of 10% AlN, though inother embodiments the AlGaN EBL composition may range from 0% to 30%AlN. Overlaying the EBL a p-type cladding comprised of GaN or AlGaNlayer with a thickness of 0.8 micron with an average composition of 4%AlN, though in other embodiments the thickness may range from 0.25 to 2μm with an average composition of 0-8% AlN. The p-cladding is terminatedat the free surface of the crystal with a highly doped p++ or p-contactlayer that enables a high quality electrical p-type contact to thedevice.

Once the laser diode epitaxial structure has been transferred to thecarrier wafer as described in this invention, wafer level processing canbe used to fabricate the dice into laser diode devices. The waferprocess steps may be similar to those described in this specificationfor more conventional laser diodes. For example, in many embodiments thebonding media and dice will have a total thickness of less than about 7μm, making it possible to use standard photoresist, photoresistdispensing technology and contact and projection lithography tools andtechniques to pattern the wafers. The aspect ratios of the features arecompatible with deposition of thin films, such as metal and dielectriclayers, using evaporators, sputter and CVD deposition tools.

The laser diode device may have laser stripe region formed in thetransferred gallium and nitrogen containing epitaxial layers. In thecase where the laser is formed on a polar c-plane, the laser diodecavity can be aligned in the m-direction with cleaved or etched mirrors.Alternatively, in the case where the laser is formed on a semipolarplane, the laser diode cavity can be aligned in a projection of ac-direction. The laser strip region has a first end and a second end andis formed on a gallium and nitrogen containing substrate having a pairof cleaved mirror structures, which face each other. The first cleavedfacet comprises a reflective coating and the second cleaved facetcomprises no coating, an antireflective coating, or exposes gallium andnitrogen containing material. The first cleaved facet is substantiallyparallel with the second cleaved facet. The first and second cleavedfacets are provided by a scribing and breaking process according to anembodiment or alternatively by etching techniques using etchingtechnologies such as reactive ion etching (RIE), inductively coupledplasma etching (ICP), or chemical assisted ion beam etching (CAIBE), orother method. Typical gases used in the etching process may include Cland/or BCl₃. The first and second mirror surfaces each comprise areflective coating. The coating is selected from silicon dioxide,hafnia, and titania, tantalum pentoxide, zirconia, includingcombinations, and the like. Depending upon the design, the mirrorsurfaces can also comprise an anti-reflective coating.

In a specific embodiment, the method of facet formation includessubjecting the substrates to a laser for pattern formation. In apreferred embodiment, the pattern is configured for the formation of apair of facets for a ridge lasers. In a preferred embodiment, the pairof facets face each other and are in parallel alignment with each other.In a preferred embodiment, the method uses a UV (355 nm) laser to scribethe laser bars. In a specific embodiment, the laser is configured on asystem, which allows for accurate scribe lines configured in a differentpatterns and profiles. In some embodiments, the laser scribing can beperformed on the back-side, front-side, or both depending upon theapplication. Of course, there can be other variations, modifications,and alternatives.

By aligning the device dice such that the intended plane of the facet iscoplanar with an easily cleaved plane of the single-crystal carrierwafer. Mechanical or laser scribes can then be used, as described above,to guide and initiate cleavage in the carrier wafer such that it islocated properly with respect to the laser die and carrier waferpatterns. Zincblende, cubic and diamond-lattice crystals work well forcleaved carriers with several sets of orthogonal cleavage planes (e.g.[110], [001], etc.). Singulation of the carrier wafers into individualdie can be accomplished either by sawing or cleaving. In the case ofsingulation using cleaving the same cleavage planes and techniques canbe used as described for facet formation.

In a specific embodiment, the method uses backside laser scribing or thelike. With backside laser scribing, the method preferably forms acontinuous line laser scribe that is perpendicular to the laser bars onthe backside of the GaN substrate. In a specific embodiment, the laserscribe is generally about 15-20 μm deep or other suitable depth.Preferably, backside scribing can be advantageous. That is, the laserscribe process does not depend on the pitch of the laser bars or otherlike pattern. Accordingly, backside laser scribing can lead to a higherdensity of laser bars on each substrate according to a preferredembodiment. In a specific embodiment, backside laser scribing, however,may lead to residue from the tape on the facets. In a specificembodiment, backside laser scribe often requires that the substratesface down on the tape. With front-side laser scribing, the backside ofthe substrate is in contact with the tape. Of course, there can be othervariations, modifications, and alternatives.

It is well known that etch techniques such as chemical assisted ion beametching (CAIBE), inductively coupled plasma (ICP) etching, or reactiveion etching (RIE) can result in smooth and vertical etched sidewallregions, which could serve as facets in etched facet laser diodes. Inthe etched facet process a masking layer is deposited and patterned onthe surface of the wafer. The etch mask layer could be comprised ofdielectrics such as silicon dioxide (SiO₂), silicon nitride(Si_(x)N_(y)), a combination thereof or other dielectric materials.Further, the mask layer could be comprised of metal layers such as Ni orCr, but could be comprised of metal combination stacks or stackscomprising metal and dielectrics. In another approach, photoresist maskscan be used either alone or in combination with dielectrics and/ormetals. The etch mask layer is patterned using conventionalphotolithography and etch steps. The alignment lithography could beperformed with a contact aligner or stepper aligner. Suchlithographically defined mirrors provide a high level of control to thedesign engineer. After patterning of the photoresist mask on top of theetch mask is complete, the patterns in then transferred to the etch maskusing a wet etch or dry etch technique. Finally, the facet pattern isthen etched into the wafer using a dry etching technique selected fromCAIBE, ICP, RIE and/or other techniques. The etched facet surfaces mustbe highly vertical of between about 87 and about 93 degrees or betweenabout 89 and about 91 degrees from the surface plane of the wafer. Theetched facet surface region must be very smooth with root mean squareroughness values of less than about 50 nm, 20 nm, 5 nm, or 1 nm. Lastly,the etched must be substantially free from damage, which could act asnon-radiative recombination centers and hence reduce the COMD threshold.CAME is known to provide very smooth and low damage sidewalls due to thechemical nature of the etch, while it can provide highly vertical etchesdue to the ability to tilt the wafer stage to compensate for anyinherent angle in etch.

In specific embodiments, multiple regions of epitaxial device materialare transferred to a carrier wafer from one or more donor wafers suchthat the regions of epitaxial device material die are positionedclosely, with separation distances of less than 50 to 100 μm. Forexample, epitaxial device dice from two or more blue emitting laserdiode epitaxial donor wafers could be transferred to a carrier wafersuch that each “chip” region of the carrier consists of one epitaxialdevice die from each donor. The transferred die could then be processedon the carrier wafer to form laser diodes or SLEDs such that each “chip”consists of two or more independently controllable laser or SLED devicesemitting at the wavelengths associated with the original donor wafers.Such a configuration is advantageous over conventional laser and SLEDdevice structures in that the multiple emitters can be arrayed much moreclosely in this configuration then they could be by bonding conventionaldevice chips to a submount. Typically, conventional device chips are onthe order of 100 μm or more in width, with the minimum width constrainedby the need for wire bonds and other means of electrical access to thedevices. A conventionally made, multi-color emitter would thereforerequire at a minimum 3-4 times as much lateral width as one made asdescribed above.

In a specific embodiment, the plurality of donor epitaxial wafers may becomprised of device layers emitting at substantially differentwavelengths. For example, a blue device emitting at around 450 nm may bebonded adjacent to both a green device emitting at around 530 nm and ared device made from AlInGaAsP layers emitting at around 630 nm. Such aconfiguration would result in a controllable light source emittingcombinations or red, green and blue light that could be used forillumination or the generation of images.

In an embodiment, the device layers comprise a super-luminescent lightemitting diode or SLED. A SLED is in many ways similar to an edgeemitting laser diode; however the emitting facet of the device isdesigned so as to have a very low reflectivity. A SLED is similar to alaser diode as it is based on an electrically driven junction that wheninjected with current becomes optically active and generates amplifiedspontaneous emission (ASE) and gain over a wide range of wavelengths.When the optical output becomes dominated by ASE there is a knee in thelight output versus current (LI) characteristic wherein the unit oflight output becomes drastically larger per unit of injected current.This knee in the LI curve resembles the threshold of a laser diode, butis much softer. A SLED would have a layer structure engineered to have alight emitting layer or layers clad above and below with material oflower optical index such that a laterally guided optical mode call beformed. The SLED would also be fabricated with features providinglateral optical confinement. These lateral confinement features mayconsist of an etched ridge, with air, vacuum, metal or dielectricmaterial surrounding the ridge and providing a low optical-indexcladding. The lateral confinement feature may also be provided byshaping the electrical contacts such that injected current is confinedto a finite region in the device. In such a “gain guided” structure,dispersion in the optical index of the light emitting layer withinjected carrier density provides the optical-index contrast needed toprovide lateral confinement of the optical mode. The emission spectralwidth is typically substantially wider (>5 nm) than that of a laserdiode and offer advantages with respect to reduced image distortion indisplays, increased eye safety, and enhanced capability in measurementand spectroscopy applications.

SLEDs are designed to have high single pass gain or amplification forthe spontaneous emission generated along the waveguide. The SLED devicewould also be engineered to have a low internal loss, preferably below 1cm⁻¹, however SLEDs can operate with internal losses higher than this.In the ideal case, the emitting facet reflectivity would be zero,however in practical applications a reflectivity of zero is difficult toachieve and the emitting facet reflectivity is designs to be less than1%, less than 0.1%, less than 0.001%, or less than 0.0001% reflectivity.Reducing the emitting facet reflectivity reduces feedback into thedevice cavity, thereby increasing the injected current density at whichthe device will begin to lase. Very low reflectivity emitting facets canbe achieved by a combination of addition of anti-reflection coatings andby angling the emitting facet relative to the SLED cavity such that thesurface normal of the facet and the propagation direction of the guidedmodes are substantially non-parallel. In general, this would mean adeviation of more than 1-2 degrees. In practice, the ideal angle dependsin part on the anti-reflection coating used and the tilt angle must becarefully designed around a null in the reflectivity versus anglerelationship for optimum performance. Tilting of the facet with respectto the propagation direction of the guided modes can be done in anydirection relative to the direction of propagation of the guided modes,though some directions may be easier to fabricate depending on themethod of facet formation. Etched facets provide high flexibility forfacet angle determination. Alternatively, a very common method toachieve an angled output for reduced constructive interference in thecavity would to curve and/or angle the waveguide with respect to acleaved facet that forms on a pre-determined crystallographic plane inthe semiconductor chip. In this configuration the angle of lightpropagation is off-normal at a specified angle designed for lowreflectivity to the cleaved facet. A low reflectivity facet may also beformed by roughening the emitting facet in such a way that lightextraction is enhanced and coupling of reflected light back into theguided modes is limited. SLEDs are applicable to all embodimentsaccording to the present invention and the device can be usedinterchangeably with laser diode device when applicable.

The laser stripe is characterized by a length and width. The lengthranges from about 50 μm to about 3000 μm, but is preferably betweenabout 10 μm and about 400 μm, between about 400 μm and about 800 μm, orabout 800 μm and about 1600 μm, but could be others such as greater than1600 μm. The stripe also has a width ranging from about 0.5 μm to about50 μm, but is preferably between about 0.8 μm and about 2.5 μm forsingle lateral mode operation or between about 2.5 μm and about 80 μmfor multi-lateral mode operation, but can be other dimensions. In aspecific embodiment, the present device has a width ranging from about0.5 μm to about 1.5 μm, a width ranging from about 1.5 μm to about 3.0μm, a width ranging from about 3.0 μm to about 360 μm, and others. In aspecific embodiment, the width is substantially constant in dimension,although there may be slight variations. The width and length are oftenformed using a masking and etching process, which are commonly used inthe art.

The laser stripe is provided by an etching process selected from dryetching or wet etching. The device also has an overlying dielectricregion, which exposes a p-type contact region. Overlying the contactregion is a contact material, which may be metal or a conductive oxideor a combination thereof. The p-type electrical contact may be depositedby thermal evaporation, electron beam evaporation, electroplating,sputtering, or another suitable technique. Overlying the polished regionof the substrate is a second contact material, which may be metal or aconductive oxide or a combination thereof and which comprises the n-typeelectrical contact. The n-type electrical contact may be deposited bythermal evaporation, electron beam evaporation, electroplating,sputtering, or another suitable technique.

An example of a processed laser diode cross-section according to oneembodiment of the present invention is shown in FIG. 10. In this examplean n-contact 801 is formed on top of n-type gallium and nitrogen contactlayer 802 and n-type cladding layer 803 that have been etched to form aridge waveguide 804. The n-type cladding layer 803 overlies an n-sidewaveguide layer or separate confinement heterostructure (SCH) layer 805and the n-side SCH overlies an active region 806 that contains lightemitting layers such as quantum wells. The active region overlies anoptional p-side SCH layer 807 and an electron blocking layer (EBL) 808.The optional p-side SCH layer overlies the p-type cladding 809 and ap-contact layer 810. Underlying the p-contact layer 810 is a metal stack811 that contains the p-type contact and bond metal used to attach thetransferred gallium and nitrogen containing epitaxial layers to thecarrier wafer 812.

Once the laser diodes have been fully processed within the gallium andnitrogen containing layers that have been transferred to the carrierwafer, the carrier wafer must be diced. Several techniques can be usedto dice the carrier wafer and the optimal process will depend on thematerial selection for the carrier wafer. As an example, for Si, InP, orGaAs carrier wafers that cleave very easily, a cleaving process can beused wherein a scribing and breaking process using conventional diamondscribe techniques may be most suitable. For harder materials such asGaN, AlN, SiC, sapphire, or others where cleaving becomes more difficulta laser scribing and breaking technique may be most suitable. In otherembodiments a sawing process may be the most optimal way to dice thecarrier wafer into individual laser chips. In a sawing process a rapidlyrotating blade with hard cutting surfaces like diamond are used,typically in conjunction with spraying water to cool and lubricate theblade. Example saw tools used to commonly dice wafers include Disco sawsand Accretech saws.

By choosing a carrier wafer material such as AlN, BeO, diamond, or SiCthat is suitable as a submount between the laser chip and the mountingsurface, the diced laser chip on the carrier wafer is in itself a chipon submount (CoS). This wafer level packaging features is a strongbenefit of the lifted-off and transferred gallium and nitrogencontaining epitaxial layer embodiment of this invention. The submountcan be the common support member wherein the phosphor member of the CPoSwould also be attached. Alternatively, the submount can be anintermediate submount intended to be mounted to the common supportmember wherein the phosphor material is attached. The submount member ischaracterized by a width, length, and thickness. In one example whereinthe submount is the common support member for the phosphor and the laserdiode, the submount would likely have a length ranging in dimension fromabout 0.5 mm to about 3 mm or about 5 mm, a width ranging from about 0.3mm to about 1 mm or from about 1 mm to 3 mm, and a thickness from about200 μm to about 1 mm. In tan example wherein the submount is anintermediate submount between the laser diode and the common supportmember it may be characterized by length ranging in dimension from about0.5 mm to about 2 mm, a width ranging from about 150 μm to about 1 mm,and the thickness may ranging from about 50 to about 500 μm.

A schematic diagram illustrating a CoS based on lifted off andtransferred epitaxial gallium and nitrogen containing layers accordingto this present invention is shown in FIG. 11. The CoS is comprised ofsubmount material 901 configured from the carrier wafer with thetransferred epitaxial material with a laser diode configured within theepitaxy 902. Electrodes 903 and 904 are electrically coupled to then-side and the p-side of the laser diode device and configured totransmit power from an external source to the laser diode to generate alaser beam output 905 from the laser diode. The electrodes areconfigured for an electrical connection to an external power source suchas a laser driver, a current source, or a voltage source. Wirebonds canbe formed on the electrodes to couple the power to the laser diodedevice. This integrated CoS device with transferred epitaxial materialoffers advantages over the conventional configuration such as size,cost, and performance due to the low thermal impedance.

Further process and device description for this embodiment describinglaser diodes formed in gallium and nitrogen containing epitaxial layersthat have been transferred from the native gallium and nitrogencontaining substrates are described in U.S. patent application Ser. No.14/312,427 and U.S. Patent Publication No. 2015/0140710, which areincorporated by reference herein. As an example, this technology of GaNtransfer can enable lower cost, higher performance, and a more highlymanufacturable process flow.

In some embodiments, the carrier wafer can be selected to provide anideal submount material for the integrated CPoS white light source. Thatis, the carrier wafer serving as the laser diode submount would alsoserve as the common support member for the laser diode and the phosphorto enable an ultra-compact CPoS integrated white light source. In oneexample, the carrier wafer is formed from silicon carbide (SiC). SiC isan ideal candidate due to its high thermal conductivity, low electricalconductivity, high hardness and robustness, and wide availability. Inother examples AlN, diamond, GaN, InP, GaAs, or other materials can beused as the carrier wafer and resulting submount for the CPoS. In oneexample, the laser chip is diced out such that there is an area in frontof the front laser facet intended for the phosphor. The phosphormaterial would then be bonded to the carrier wafer and configured forlaser excitation according to this embodiment.

After fabrication of the laser diode on a submount member, in aembodiments of this invention the construction of the integrated whitesource would proceed to integration of the phosphor with the laser diodeand common support member. Phosphor selection is a key considerationwithin the laser based integrated white light source. The phosphor mustbe able to withstand the extreme optical intensity and associatedheating induced by the laser excitation spot without severe degradation.Important characteristics to consider for phosphor selection include:

-   -   A high conversion efficiency of optical excitation power to        white light lumens. In the example of a blue laser diode        exciting a yellow phosphor, a conversion efficiency of over 150        lumens per optical watt, or over 200 lumens per optical watt, or        over 300 lumens per optical watt is desired.    -   A high optical damage threshold capable of withstanding 1-20 W        of laser power in a spot comprising a diameter of 1 mm, 500 μm,        200 μm, 100 μm, or even 50 μm.    -   High thermal damage threshold capable of withstanding        temperatures of over 150° C., over 200° C., or over 300° C.        without decomposition.    -   A low thermal quenching characteristic such that the phosphor        remains efficient as it reaches temperatures of over 150° C.,        200° C., or 250° C.    -   A high thermal conductivity to dissipate the heat and regulate        the temperature. Thermal conductivities of greater than 3 W/m-K,        greater than 5 W/m-K, greater than 10 W/m-K, and even greater        than 15 W/m-K are desirable.    -   A proper phosphor emission color for the application.    -   A suitable porosity characteristic that leads to the desired        scattering of the coherent excitation without unacceptable        reduction in thermal conductivity or optical efficiency.    -   A proper form factor for the application. Such form factors        include, but are not limited to blocks, plates, disks, spheres,        cylinders, rods, or a similar geometrical element. Proper choice        will be dependent on whether phosphor is operated in        transmissive or reflective mode and on the absorption length of        the excitation light in the phosphor.    -   A surface condition optimized for the application. In an        example, the phosphor surfaces can be intentionally roughened        for improved light extraction.

In a preferred embodiment, a blue laser diode operating in the 420 nm to480 nm wavelength range would be combined with a phosphor materialproviding a yellowish emission in the 560 nm to 580 nm range such thatwhen mixed with the blue emission of the laser diode a white light isproduced. For example, to meet a white color point on the black bodyline the energy of the combined spectrum may be comprised of about 30%from the blue laser emission and about 70% from the yellow phosphoremission. In other embodiments phosphors with red, green, yellow, andeven blue emission can be used in combination with the laser diodeexcitation sources in the violet, ultra-violet, or blue wavelength rangeto produce a white light with color mixing. Although such white lightsystems may be more complicated due to the use of more than one phosphormember, advantages such as improved color rendering could be achieved.

In an example, the light emitted from the a laser diodes is partiallyconverted by the phosphor element. In an example, the partiallyconverted light emitted generated in the phosphor element results in acolor point, which is white in appearance. In an example, the colorpoint of the white light is located on the Planckian blackbody locus ofpoints. In an example, the color point of the white light is locatedwithin du‘v’ of less than 0.010 of the Planckian blackbody locus ofpoints. In an example, the color point of the white light is preferablylocated within du‘v’ of less than 0.03 of the Planckian blackbody locusof points.

The phosphor material can be operated in a transmissive mode, areflective mode, or a combination of a transmissive mode and reflectivemode, or other modes. The phosphor material is characterized by aconversion efficiency, a resistance to thermal damage, a resistance tooptical damage, a thermal quenching characteristic, a porosity toscatter excitation light, and a thermal conductivity. In a preferredembodiment the phosphor material is comprised of a yellow emitting YAGmaterial doped with Ce with a conversion efficiency of greater than 100lumens per optical watt, greater than 200 lumens per optical watt, orgreater than 300 lumens per optical watt, and can be a polycrystallineceramic material or a single crystal material.

In some embodiments of the present invention, the environment of thephosphor can be independently tailored to result in high efficiency withlittle or no added cost. Phosphor optimization for laser diodeexcitation can include high transparency, scattering or non-scatteringcharacteristics, and use of ceramic phosphor plates. Decreasedtemperature sensitivity can be determined by doping levels. A reflectorcan be added to the backside of a ceramic phosphor, reducing loss. Thephosphor can be shaped to increase in-coupling, increase out-coupling,and/or reduce back reflections. Surface roughening is a well-known meansto increase extraction of light from a solid material. Coatings,mirrors, or filters can be added to the phosphors to reduce the amountof light exiting the non-primary emission surfaces, to promote moreefficient light exit through the primary emission surface, and topromote more efficient in-coupling of the laser excitation light. Ofcourse, there can be additional variations, modifications, andalternatives.

In some embodiments, certain types of phosphors will be best suited inthis demanding application with a laser excitation source. As anexample, ceramic yttrium aluminum garnets (YAG) doped with Ce³⁺ ions, orYAG based phosphors can be ideal candidates. They are doped with speciessuch as Ce to achieve the proper emission color and are often comprisedof a porosity characteristic to scatter the excitation source light, andnicely break up the coherence in laser excitation. As a result of itscubic crystal structure the YAG:Ce can be prepared as a highlytransparent single crystal as well as a polycrystalline bulk material.The degree of transparency and the luminescence are depending on thestoichiometric composition, the content of dopant, and entire processingand sintering route. The transparency and degree of scattering centerscan be optimized for a homogenous mixture of blue and yellow light. TheYAG:CE can be configured to emit a green emission. In some embodimentsthe YAG can be doped with Eu to emit a red emission.

In a preferred embodiment according to this invention, the white lightsource is configured with a ceramic polycrystalline YAG:Ce phosphorscomprising an optical conversion efficiency of greater than 100 lumensper optical excitation watt, of greater than 200 lumens per opticalexcitation watt, or even greater than 300 lumens per optical excitationwatt. Additionally, the ceramic YAG:Ce phosphors is characterized by atemperature quenching characteristics above 150° C., above 200° C., orabove 250° C. and a high thermal conductivity of 5-10 W/m-K toeffectively dissipate heat to a heat sink member and keep the phosphorat an operable temperature.

In another preferred embodiment according to this invention, the whitelight source is configured with a single crystal phosphor (SCP) such asYAG:Ce. In one example the Ce:Y₃Al₅O₁₂ SCP can be grown by theCzochralski technique. In this embodiment according the presentinvention the SCP based on YAG:Ce is characterized by an opticalconversion efficiency of greater than 100 lumens per optical excitationwatt, of greater than 200 lumens per optical excitation watt, or evengreater than 300 lumens per optical excitation watt. Additionally, thesingle crystal YAG:Ce phosphors is characterized by a temperaturequenching characteristics above 150° C., above 200° C., or above 300° C.and a high thermal conductivity of 8-20 W/m-K to effectively dissipateheat to a heat sink member and keep the phosphor at an operabletemperature. In addition to the high thermal conductivity, high thermalquenching threshold, and high conversion efficiency, the ability toshape the phosphors into tiny forms that can act as ideal “point”sources when excited with a laser is an attractive feature.

In some embodiments the YAG:Ce can be configured to emit a yellowemission. In alternative or the same embodiments a YAG:Ce can beconfigured to emit a green emission. In yet alternative or the sameembodiments the YAG can be doped with Eu to emit a red emission. In someembodiments a LuAG is configured for emission. In alternativeembodiments, silicon nitrides or aluminum-oxi-nitrides can be used asthe crystal host materials for red, green, yellow, or blue emissions.

In an alternative embodiment, a powdered single crystal or ceramicphosphor such as a yellow phosphor or green phosphor is included. Thepowdered phosphor can be dispensed on a transparent member for atransmissive mode operation or on a solid member with a reflective layeron the back surface of the phosphor or between the phosphor and thesolid member to operate in a reflective mode. The phosphor powder may beheld together in a solid structure using a binder material wherein thebinder material is preferable in inorganic material with a high opticaldamage threshold and a favorable thermal conductivity. The phosphorpower may be comprised of a colored phosphors and configured to emit awhite light when excited by and combined with the blue laser beam orexcited by a violet laser beam. The powdered phosphors could becomprised of YAG, LuAG, or other types of phosphors.

In one embodiment of the present invention the phosphor materialcontains a yttrium aluminum garnet host material and a rare earth dopingelement, and others. In an example, the wavelength conversion element isa phosphor which contains a rare earth doping element, selected from aof Ce, Nd, Er, Yb, Ho, Tm, Dy and Sm, combinations thereof, and thelike. In an example, the phosphor material is a high-density phosphorelement. In an example, the high-density phosphor element has a densitygreater than 90% of pure host crystal. Cerium (III)-doped YAG (YAG:Ce³⁺,or Y₃Al₅O₁₂:Ce³⁺) can be used wherein the phosphor absorbs the lightfrom the blue laser diode and emits in a broad range from greenish toreddish, with most of output in yellow. This yellow emission combinedwith the remaining blue emission gives the “white” light, which can beadjusted to color temperature as warm (yellowish) or cold (bluish)white. The yellow emission of the Ce³⁺:YAG can be tuned by substitutingthe cerium with other rare earth elements such as terbium and gadoliniumand can even be further adjusted by substituting some or all of thealuminum in the YAG with gallium.

In alternative examples, various phosphors can be applied to thisinvention, which include, but are not limited to organic dyes,conjugated polymers, semiconductors such as AlInGaP or InGaN, yttriumaluminum garnets (YAGs) doped with Ce³⁺ ions(Y_(1-a)Gd_(a))₃(Al_(1-b)Ga_(b))₅O₁₂:Ce³⁺, SrGa₂S₄:Eu²⁺, SrS:Eu²⁺,terbium aluminum based garnets (TAGs) (Tb₃Al₅O₅), colloidal quantum dotthin films containing CdTe, ZnS, ZnSe, ZnTe, CdSe, or CdTe.

In further alternative examples, some rare-earth doped SiAlONs can serveas phosphors. Europium(II)-doped β-SiAlON absorbs in ultraviolet andvisible light spectrum and emits intense broadband visible emission. Itsluminance and color does not change significantly with temperature, dueto the temperature-stable crystal structure. In an alternative example,green and yellow SiAlON phosphor and a red CaAlSiN₃-based (CASN)phosphor may be used.

In yet a further example, white light sources can be made by combiningnear ultraviolet emitting laser diodes with a mixture of high efficiencyeuropium based red and blue emitting phosphors plus green emittingcopper and aluminum doped zinc sulfide (ZnS:Cu,Al).

In an example, a phosphor or phosphor blend can be selected from a of(Y, Gd, Tb, Sc, Lu, La)₃(Al, Ga, In)₅O₁₂:Ce³⁺, SrGa₂S₄:Eu²⁺, SrS:Eu²⁺,and colloidal quantum dot thin films comprising CdTe, ZnS, ZnSe, ZnTe,CdSe, or CdTe. In an example, a phosphor is capable of emittingsubstantially red light, wherein the phosphor is selected from a of thegroup consisting of (Gd,Y,Lu,La)₂O₃:Eu³⁺, Bi³⁺; (Gd,Y,Lu,La)₂O₂S:Eu³⁺,Bi³⁺; (Gd,Y,Lu,La)VO₄:Eu³⁺, Bi³⁺; Y₂(O,S)₃:Eu³⁺;Ca_(1-x)Mo_(1-y)Si_(y)O₄: where 0.05<x<0.5, 0<y<0.1;(Li,Na,K)₅Eu(W,Mo)O₄; (Ca,Sr)S:Eu²⁺; SrY₂S₄:Eu²⁺; CaLa₂S₄:Ce³⁺;(Ca,Sr)S:Eu²⁺; 3.5MgO×0.5MgF₂×GeO₂:Mn⁴⁺ (MFG);(Ba,Sr,Ca)Mg_(x)P₂O₇:En²⁺, Mn²⁺; (Y,Lu)₂WO₆:Eu³⁺, Mo⁶⁺;(Ba,Sr,Ca)₃Mg_(x)Si₂O₈:Eu²⁺, Mn²⁺, wherein 1<x<2;(RE_(1-y)Ce_(y))Mg_(2-x)Li_(x)Si_(3-x)P_(x)O₁₂, where RE is at least oneof Sc, Lu, Gd, Y, and Tb, 0.0001<x<0.1 and 0.001<y<0.1; (Y, Gd, Lu,La)_(2-x)Eu_(x)W_(1-y)Mo_(y)O₆, where 0.5<x<1.0, 0.01<y<1.0;(SrCa)_(1-x)Eu_(x)Si₅N₈, where 0.01<x<0.3; SrZnO₂:Sm⁺³; M_(m)O_(n)X,wherein M is selected from the group of Sc, Y, a lanthanide, an alkaliearth metal and mixtures thereof; X is a halogen; 1<m<3; and 1<n<4, andwherein the lanthanide doping level can range from 0.1 to 40% spectralweight; and Eu³⁺ activated phosphate or borate phosphors; and mixturesthereof. Further details of other phosphor species and relatedtechniques can be found in U.S. Pat. No. 8,956,894, in the name ofRaring et al. issued Feb. 17, 2015, and titled “White light devicesusing non-polar or semipolar gallium containing materials andphosphors”, which is commonly owned, and hereby incorporated byreference herein.

In some embodiments of the present invention, ceramic phosphor materialsare embedded in a binder material such as silicone. This configurationis typically less desirable because the binder materials often have poorthermal conductivity, and thus get very hot wherein the rapidly degradeand even burn. Such “embedded” phosphors are often used in dynamicphosphor applications such as color wheels where the spinning wheelcools the phosphor and spreads the excitation spot around the phosphorin a radial pattern.

Sufficient heat dissipation from the phosphor is a critical designconsideration for the integrated white light source based on laser diodeexcitation. Specifically, the optically pumped phosphor system hassources of loss in the phosphor that result is thermal energy and hencemust be dissipated to a heat-sink for optimal performance. The twoprimary sources of loss are the Stokes loss which is a result ofconverting photons of higher energy to photons of lower energy such thatdifference in energy is a resulting loss of the system and is dissipatedin the form of heat. Additionally, the quantum efficiency or quantumyield measuring the fraction of absorbed photons that are successfullyre-emitted is not unity such that there is heat generation from otherinternal absorption processes related to the non-converted photons.Depending on the excitation wavelength and the converted wavelength, theStokes loss can lead to greater than 10%, greater than 20%, and greaterthan 30%, and greater loss of the incident optical power to result inthermal power that must be dissipated. The quantum losses can lead to anadditional 10%, greater than 20%, and greater than 30%, and greater ofthe incident optical power to result in thermal power that must bedissipated. With laser beam powers in the 1 W to 100 W range focused tospot sizes of less than 1 mm in diameter, less than 500 μm in diameter,or even less than 100 μm in diameter, power densities of over 1 W/mm²,100 W/mm², or even over 2,500 W/mm² can be generated. As an example,assuming that the spectrum is comprised of 30% of the blue pump lightand 70% of the converted yellow light and a best case scenario on Stokesand quantum losses, we can compute the dissipated power density in theform of heat for a 10% total loss in the phosphor at 0.1 W/mm², 10W/mm², or even over 250 W/mm². Thus, even for this best case scenarioexample, this is a tremendous amount of heat to dissipate. This heatgenerated within the phosphor under the high intensity laser excitationcan limit the phosphor conversion performance, color quality, andlifetime.

For optimal phosphor performance and lifetime, not only should thephosphor material itself have a high thermal conductivity, but it shouldalso be attached to the submount or common support member with a highthermal conductivity joint to transmit the heat away from the phosphorand to a heat-sink. In this invention, the phosphor is either attachedto the common support member as the laser diode as in the CPoS or isattached to an intermediate submount member that is subsequentlyattached to the common support member. Candidate materials for thecommon support member or intermediate submount member are SiC, AlN, BeO,diamond, copper, copper tungsten, sapphire, aluminum, or others. Theinterface joining the phosphor to the submount member or common supportmember must be carefully considered. The joining material should becomprised of a high thermal conductivity material such as solder (orother) and be substantially free from voids or other defects that canimpede heat flow. In some embodiments, glue materials can be used tofasten the phosphor. Ideally the phosphor bond interface will have asubstantially large area with a flat surface on both the phosphor sideand the support member sides of the interface.

In the present invention, the laser diode output beam must be configuredto be incident on the phosphor material to excite the phosphor. In someembodiments the laser beam may be directly incident on the phosphor andin other embodiments the laser beam may interact with an optic,reflector, waveguide, or other object to manipulate the beam prior toincidence on the phosphor. Examples of such optics include, but are notlimited to ball lenses, aspheric collimator, aspheric lens, fast or slowaxis collimators, dichroic mirrors, turning mirrors, optical isolators,but could be others.

In some embodiments, the apparatus typically has a free space with anon-guided laser beam characteristic transmitting the emission of thelaser beam from the laser device to the phosphor material. The laserbeam spectral width, wavelength, size, shape, intensity, andpolarization are configured to excite the phosphor material. The beamcan be configured by positioning it at the precise distance from thephosphor to exploit the beam divergence properties of the laser diodeand achieve the desired spot size. In one embodiment, the incident anglefrom the laser to the phosphor is optimized to achieve a desired beamshape on the phosphor. For example, due to the asymmetry of the laseraperture and the different divergent angles on the fast and slow axis ofthe beam the spot on the phosphor produced from a laser that isconfigured normal to the phosphor would be elliptical in shape,typically with the fast axis diameter being larger than the slow axisdiameter. To compensate this, the laser beam incident angle on thephosphor can be optimized to stretch the beam in the slow axis directionsuch that the beam is more circular on phosphor. In other embodimentsfree space optics such as collimating lenses can be used to shape thebeam prior to incidence on the phosphor. The beam can be characterizedby a polarization purity of greater than 50% and less than 100%. As usedherein, the term “polarization purity” means greater than 50% of theemitted electromagnetic radiation is in a substantially similarpolarization state such as the transverse electric (TE) or transversemagnetic (TM) polarization states, but can have other meaningsconsistent with ordinary meaning.

The white light apparatus also has an electrical input interfaceconfigured to couple electrical input power to the laser diode device togenerate the laser beam and excite the phosphor material. In an example,the laser beam incident on the phosphor has a power of less than 0.1 W,greater than 0.1 W, greater than 0.5 W, greater than 1 W, greater than 5W, greater than 10 W, or greater than 20 W. The white light sourceconfigured to produce greater than 1 lumen, 10 lumens, 100 lumens, 1000lumens, 10,000 lumens, or greater of white light output.

The support member is configured to transport thermal energy from the atleast one laser diode device and the phosphor material to a heat sink.The support member is configured to provide thermal impedance of lessthan 10 degrees Celsius per watt, less than 5 degrees Celsius per watt,or less than 3 degrees Celsius per watt of dissipated powercharacterizing a thermal path from the laser device to a heat sink. Thesupport member is comprised of a thermally conductive material such ascopper with a thermal conductivity of about 400 W/(m-K), aluminum with athermal conductivity of about 200 W/(mK), 4H—SiC with a thermalconductivity of about 370 W/(m-K), 6H—SiC with a thermal conductivity ofabout 490 W/(m-K), AlN with a thermal conductivity of about 230 W/(m-K),a synthetic diamond with a thermal conductivity of about >1000 W/(m-K),sapphire, or other metals, ceramics, or semiconductors. The supportmember may be formed from a growth process such as SiC, AlN, orsynthetic diamond, and then mechanically shaped by machining, cutting,trimming, or molding. Alternatively the support member may be formedfrom a metal such as copper, copper tungsten, aluminum, or other bymachining, cutting, trimming, or molding.

Currently, solid state lighting is dominated by systems utilizing blueor violet emitting light emitting diodes (LEDs) to excite phosphorswhich emit a broader spectrum. The combined spectrum of the so calledpump LEDs and the phosphors can be optimized to yield white lightspectra with controllable color point and good color rendering index.Peak wall plug efficiencies for state of the art LEDs are quite high,above 70%, such that LED based white light bulbs are now the leadinglighting technology for luminous efficacy. As laser light sources,especially high-power blue laser diodes made from gallium and nitrogencontaining material based novel manufacture processes, have shown manyadvantageous functions on quantum efficiency, power density, modulationrate, surface brightness over conventional LEDs. This opens up theopportunity to use lighting fixtures, lighting systems, displays,projectors and the like based on solid-state light sources as a means oftransmitting information with high bandwidth using visible light. Italso enables utilizing the modulated laser signal or direct laser lightspot manipulation to measure and or interact with the surroundingenvironment, transmit data to other electronic systems and responddynamically to inputs from various sensors. Such applications are hereinreferred to as “smart lighting” applications.

In some embodiments, the present invention provides novel uses andconfigurations of gallium and nitrogen containing laser diodes incommunication systems such as visible light communication systems. Morespecifically the present invention provides communication systemsrelated to smart lighting applications with gallium and nitrogen basedlasers light sources coupled to one or more sensors with a feedback loopor control circuitry to trigger the light source to react with one ormore predetermined responses and combinations of smart lighting andvisible light communication. In these systems, light is generated usinglaser devices which are powered by one or more laser drivers. In someembodiments, individual laser devices are used and optical elements areprovided to combine the red, green and blue spectra into a white lightspectrum. In other embodiments, blue or violet laser light is providedby a laser source and is partially or fully converted by a wavelengthconverting element into a broader spectrum of longer wavelength lightsuch that a white light spectrum is produced.

The blue or violet laser devices illuminate a wavelength convertingelement which absorbs part of the pump light and reemits a broaderspectrum of longer wavelength light. The light absorbed by thewavelength converting element is referred to as the “pump” light. Thelight engine is configured such that some portion of both light from thewavelength converting element and the unconverted pump light are emittedfrom the light-engine. When the non-converted, blue pump light and thelonger wavelength light emitted by the wavelength converting element arecombined, they may form a white light spectrum. In an example, thepartially converted light emitted generated in the wavelength conversionelement results in a color point, which is white in appearance. In anexample, the color point of the white light is located on the Planckianblackbody locus of points. In an example, the color point of the whitelight is located within du‘v’ of less than 0.010 of the Planckianblackbody locus of points. In an example, the color point of the whitelight is preferably located within du‘v’ of less than 0.03 of thePlanckian blackbody locus of points.

In an example, the wavelength conversion element is a phosphor whichcontains garnet host material and a doping element. In an example, thewavelength conversion element is a phosphor, which contains an yttriumaluminum garnet host material and a rare earth doping element, andothers. In an example, the wavelength conversion element is a phosphorwhich contains a rare earth doping element, selected from one or more ofNd, Cr, Er, Yb, Nd, Ho, Tm Cr, Dy, Sm, Tb and Ce, combinations thereof,and the like. In an example, the wavelength conversion element is aphosphor which contains oxy-nitrides containing one or more of Ca, Sr,Ba, Si, Al with or without rare-earth doping. In an example, thewavelength conversion element is a phosphor which contains alkalineearth silicates such as M₂SiO₄:Eu²⁺ (where M is one or more of Ba²⁺, Sr⁺and Ca²⁺. In an example, the wavelength conversion element is a phosphorwhich contains Sr₂LaAlOs:Ce³⁺, Sr₃SiO₅:Ce³⁺ or Mn⁴⁺-doped fluoridephosphors. In an example, the wavelength conversion element is ahigh-density phosphor element In an example, the wavelength conversionelement is a high-density phosphor element with density greater than 90%of pure host crystal. In an example, the wavelength converting materialis a powder. In an example, the wavelength converting material is apowder suspended or embedded in a glass, ceramic or polymer matrix. Inan example, the wavelength converting material is a single crystallinemember. In an example, the wavelength converting material is a powdersintered to density of greater than 75% of the fully dense material. Inan example, the wavelength converting material is a sintered mix ofpowders with varying composition and/or index of refraction. In anexample, the wavelength converting element is one or more species ofphosphor powder or granules suspended in a glassy or polymer matrix. Inan example, the wavelength conversion element is a semiconductor. In anexample, the wavelength conversion element contains quantum dots ofsemiconducting material. In an example, the wavelength conversionelement is comprised by semiconducting powder or granules.

For laser diodes the phosphor may be remote from the laser die, enablingthe phosphor to be well heat sunk, enabling high input power density.This is an advantageous configuration relative to LEDs, where thephosphor is typically in contact with the LED die. While remote-phosphorLEDs do exist, because of the large area and wide emission angle ofLEDs, remote phosphors for LEDs have the disadvantage of requiringsignificantly larger volumes of phosphor to efficiently absorb andconvert all of the LED light, resulting in white light emitters withlarge emitting areas and low luminance.

For LEDs, the phosphor emits back into the LED die where the light fromthe phosphor can be lost due to absorption. For laser diode modules, theenvironment of the phosphor can be independently tailored to result inhigh efficiency with little or no added cost. Phosphor optimization forlaser diode modules can include highly transparent, non-scattering,ceramic phosphor plates. Decreased temperature sensitivity can bedetermined by doping levels. A reflector can be added to the backside ofa ceramic phosphor, reducing loss. The phosphor can be shaped toincrease in-coupling and reduce back reflections. Of course, there canbe additional variations, modifications, and alternatives.

For laser diodes, the phosphor or wavelength converting element can beoperated in either a transmission or reflection mode. In a transmissionmode, the laser light is shown through the wavelength convertingelement. The white light spectrum from a transmission mode device is thecombination of laser light not absorbed by the phosphor and the spectrumemitted by the wavelength converting element. In a reflection mode, thelaser light is incident on the first surface of the wavelengthconverting element. Some fraction of the laser light is reflected off ofthe first surface by a combination of specular and diffuse reflection.Some fraction of the laser light enters the phosphor and is absorbed andconverted into longer wavelength light. The white light spectrum emittedby the reflection mode device is comprised by the spectrum from thewavelength converting element, the fraction of the laser light diffuselyreflected from the first surface of the wavelength converting elementand any laser light scattered from the interior of the wavelengthconverting element.

In a specific embodiment, the laser light illuminates the wavelengthconverting element in a reflection mode. That is, the laser light isincident on and collected from the same side of the wavelengthconverting element. The element may be heat sunk to the emitter packageor actively cooled. Rough surface is for scattering and smooth surfaceis for specular reflection. In some cases such as with a single crystalphosphor a rough surface with or without an AR coating of the wavelengthconverting element is provided to get majority of excitation light intophosphor for conversion and Lambertian emission while scattering some ofthe excitation light from the surface with a similar Lambertian as theemitted converted light. In other embodiments such as ceramic phosphorswith internal built-in scattering centers are used as the wavelengthconverting elements, a smooth surface is provided to allow all laserexcitation light into the phosphor where blue and wavelength convertedlight exits with a similar Lambertian pattern.

In a specific embodiment, the laser light illuminates the wavelengthconverting element in a transmission mode. That is, the laser light isincident on one side of the element, traverses through the phosphor, ispartially absorbed by the element and is collected from the oppositeside of the phosphor.

The wavelength converting elements, in general, can themselves containscattering elements. When laser light is absorbed by the wavelengthconverting element, the longer wavelength light that is emitted by theelement is emitted across a broad range of directions. In bothtransmission and reflection modes, the incident laser light must bescattered into a similar angular distribution in order to ensure thatthe resulting white light spectrum is substantially the same when viewedfrom all points on the collecting optical elements. Scattering elementsmay be added to the wavelength converting element in order to ensure thelaser light is sufficiently scattered. Such scattering elements mayinclude: low index inclusions such as voids, spatial variation in theoptical index of the wavelength converting element which could beprovided as an example by suspending particles of phosphor in a matrixof a different index or sintering particles of differing composition andrefractive index together, texturing of the first or second surface ofthe wavelength converting element, and the like.

In a specific embodiment, a laser or SLED driver module is provided. Forexample, the laser driver module generates a drive current, with thedrive currents being adapted to drive a laser diode to transmit one ormore signals such as digitally encoded frames of images, digital oranalog encodings of audio and video recordings or any sequences ofbinary values. In a specific embodiment, the laser driver module isconfigured to generate pulse-modulated signals at a frequency range ofabout 50 to 300 MHz, 300 MHz to 1 GHz or 1 GHz to 100 GHz. In anotherembodiment the laser driver module is configured to generate multiple,independent pulse-modulated signal at a frequency range of about 50 to300 MHz, 200 MHz to 1 GHz or 1 GHz to 100 GHz. In an embodiment, thelaser driver signal can be modulated by an analog voltage or currentsignal.

FIG. 12A is a functional block diagram for a laser-based white lightsource containing a blue pump laser and a wavelength converting elementaccording to an embodiment of the present invention. In someembodiments, the white light source is used as a “light engine” for VLCor smart lighting applications. Referring to FIG. 12A, a blue or violetlaser device 1202 emitting a spectrum with a center point wavelengthbetween 390 and 480 nm is provided. The light from the blue laser device1202 is incident on a wavelength converting element 1203 which partiallyor fully converts the blue light into a broader spectrum of longerwavelength light such that a white light spectrum is produced. A laserdriver 1201 is provided which powers the laser device 1202. In someembodiments, one or more beam shaping optical elements 1204 may beprovided in order to shape or focus the white light spectrum.Optionally, the one or more beam shaping optical elements 1204 can beone selected from slow axis collimating lens, fast axis collimatinglens, aspheric lens, ball lens, total internal reflector (TIR) optics,parabolic lens optics, refractive optics, or a combination of above. Inother embodiments, the one or more beam shaping optical elements 1204can be disposed prior to the laser light incident to the wavelengthconverting element 1203.

FIG. 12B is a functional block diagram for a laser-based white lightsource containing multiple blue pump lasers and a wavelength convertingelement according to another embodiment of the present invention.Referring to FIG. 12B, a laser driver 1205 is provided, which delivers adelivers a controlled amount of current at a sufficiently high voltageto operate there laser diodes 1206, 1207 and 1208. The three blue laserdevices 1206, 1207 and 1208 are configured to have their emitted lightto be incident on a wavelength converting element 1209 in either atransmission or reflection mode. The wavelength converting element 1209absorbs a part or all the blue laser light and emits photons with longerwavelengths. The spectra emitted by the wavelength converting element1209 and any remaining laser light are collected by beam shaping opticalelements 1210, such as lenses or mirrors, which direct the light with apreferred direction and beam shape. Optionally, the wavelengthconverting element 1209 is a phosphor-based material. Optionally, morethan one wavelength converting elements can be used. Optionally, thebean shaping optical elements can be one or a combination of moreselected the list of slow axis collimating lens, fast axis collimatinglens, aspheric lens, ball lens, total internal reflector (TIR) optics,parabolic lens optics, refractive optics, and others. Optionally, thebeam shaping optical element is implemented before the laser light hitsthe wavelength converting element.

It is to be understood that, in the embodiments, the light engine is notlimited to a specific number of laser devices. FIG. 12B shows afunctional diagram for an example of laser-diode-based light engine forVLC or smart lighting applications containing multiple blue or violetlaser diodes, for example, a first blue laser diode 1206, a second bluelaser diode 1207 and a third blue laser diode 1208 are provided. Thelight from all three is incident on a wavelength converting element 1209which partially or fully converts the blue light into a broader spectrumof longer wavelength light such that a white light spectrum is produced.In some embodiments, the laser light engine may contain 2, 4, 5, 6 ormore blue or violet laser diodes. In an example, the light enginecomprises two or more laser or SLED “pump” light-sources emitting withcenter wavelengths between 380 nm and 480 nm, with the centerwavelengths of individual pump light sources separated by at least 5 nm.The spectral width of the laser light source is preferably less than 2nm, though widths up to 75% of the center wavelength separation would beacceptable. A laser driver 1205 is provided to drive the laser devicesand is configured such that one or more of the laser devices areindividually addressable and can be powered independently of the rest.In some embodiments, one or more beam shaping optical elements 1210 isprovided in order to shape or focus the white light spectrum.

FIG. 12C is a functional block diagram of a laser based white lightsource containing a blue pump laser, a wavelength converting element,and red and green laser diodes according to yet another embodiment ofthe present invention. Referring to FIG. 12C, a laser driver 1211 isprovided, which delivers a controlled amount of current at asufficiently high voltage to operate the laser diodes 1212, 1213 and1214. A blue laser device 1212 is provided to emit light configured tobe incident on a wavelength converting element 1215 in either atransmission or reflection mode. The wavelength converting element 1215absorbs a part or all of the blue laser light emitted from the bluelaser diode 1212 and emits photons with longer wavelengths. Optionally,the wavelength converting element 1215 partially or fully converts theblue light into a broader spectrum of longer wavelength light such thata white light spectrum is produced. In addition, a red light emittinglaser diode 1213 and a green light emitting laser diode 1214 areseparately provided. In this configuration, the red and green laserlights are not incident on the wavelength converting element 1215,though it is possible for the red and green light to be incident on thewavelength converting element without conversion of the red and greenlaser light. The spectra emitted by the wavelength converting element1215 and any remaining laser light from the green and red laser devicesare collected by a beam shaping optical elements 1216, such as lenses ormirrors, which direct the light with a preferred direction and beamshape.

In a specific embodiment, the light engine consists of two or more laseror SLED “pump” light-sources emitting with center wavelengths between380 nm and 480 nm, with the center wavelengths of individual pump lightsources separated by at least 5 nm. The spectral width of the laserlight source is preferably less than 2 nm, though widths up to 75% ofthe center wavelength separation would be acceptable. A laser driver1211 is provided which powers the laser devices and is configured suchthat the laser devices are individually addressable and can be poweredindependently of the rest. In some embodiments, one or more beam shapingoptical elements 1216 is provided in order to shape or focus the whitelight spectrum from the wavelength converting element 1215. The beamshaping optical elements 1216 may also be configured to combine the redand green laser light with the white light spectrum. In someembodiments, each of the red and green laser light is also incident onthe wavelength converting element 1215 and overlaps spatially with thewavelength converted blue light. The wavelength converting elementmaterial 1215 is chosen such that the non-converted (red or green) laserlight is scattered with a similar radiation pattern to the wavelengthconverted blue light, but with minimal loss due to absorption.

In another specific embodiment, the present invention provideslight-engine with a wavelength converting element, that can function asa white light source for general lighting and display applications andalso as an emitter for visible light communication. The emitter consistsof three or more laser or SLED light sources. At least one light sourceemits a spectrum with a center wavelength in the range of 380-480 nm andacts as a blue light source. At least one light emits a spectrum with acenter wavelength in the range of 480-550 nm and acts as a green lightsource. At least one light emits a spectrum with a center wavelength inthe range 600-670 nm and acts as a red light source. Each light sourceis individually addressable, such that they may be operatedindependently of one another and act as independent communicationchannels, or in the case of multiple emitters in the red, green or bluewavelength ranges the plurality of light sources in each range may beaddressed collectively, though the plurality of sources in each rangeare addressable independently of the sources in the other wavelengthranges. One or more of the light sources emitting in the blue range ofwavelengths illuminates a wavelength converting element which absorbspart of the pump light and reemits a broader spectrum of longerwavelength light. The light engine is configured such that both lightfrom the wavelength converting element and the plurality of lightsources are emitted from the light-engine. This embodiment functions asa light source with tunable color, allowing for a plurality ofcombinations of red, green and blue light. It also provides a broadwhite light spectrum via the wavelength converting element as a high CRIwhite light source, with the red and green channels capable of beingoverlaid on the broad white light spectrum to dynamically shift thecolor point.

Optionally, the non-converted laser devices need not have spectracorresponding to red light and green light. For example, thenon-converted laser device might emit in the infra-red at wavelengthsbetween 800 nm and 2 microns wavelength. For example, such devices couldbe formed on InP substrates using the InGaAsP material system or formedon GaAs substrates using the InAlGaAsP. Moreover, such laser devicescould be formed on the same carrier wafer as the visible blue GaN laserdiode source using the epitaxy transfer technology according to thisinvention. Such a device would be advantageous for communication as theinfra-red device, while not adding to the luminous efficacy of the lightengine, would provide a non-visible channel for communications. Thiswould allow for data transfer to continue under a broader range ofconditions. For example, a VLC-enabled light engine using only visibleemitters would be incapable of effectively transmitting data when thelight source is nominally turned off as one would find in, for example,a movie theater, conference room during a presentation, a moodily litrestaurant or bar, or a bed-room at night among others. In anotherexample, the non-converted laser device might emit a spectrumcorresponding to blue or violet light, with a center wavelength between390 and 480 nm. In another embodiment, the non-converted blue or violetlaser may either be not incident on the wavelength converting elementand combined with the white light spectrum in beam shaping and combiningoptics.

In still another embodiment, the present invention provides a lightengine that can function as a white light source for general lightingapplications as well as displays and also as an emitter for visiblelight communication. The emitter consists of at least one or more laseror SLED “pump” light sources emitting with center wavelengths between380 nm and 480 nm which act as a blue light source. The light enginealso contains one or more laser or SLED light sources emitting atnon-visible wavelengths longer than 700 nm. One or more of the lightsources emitting in the blue range of wavelengths illuminates awavelength converting element which absorbs part of the pump light andreemits a broader spectrum of longer wavelength light. The light engineis configured such that both light from the wavelength convertingelement and the plurality of light sources are emitted from thelight-engine. Each pump light source is individually addressable, suchthat they may be operated independently of one another and act asindependent communication channels. The wavelength converting element isthe same as that previously described. The non-visible light sources arealso individually addressable and can be used to transmit data atwavelengths that are not visible to the human eye. In an example, thenon-visible lasers or SLEDs may emit at typical telecommunicationwavelengths such as between 1.3 and 1.55 microns. In another example,the non-visible lasers or SLEDs may emit spectra with center wavelengthsbetween 800 nm and 2 microns.

FIG. 12D is a functional block diagram of a laser based white lightsource containing blue, green and red laser devices and no wavelengthconverting element according to still another embodiment of the presentinvention. Referring to FIG. 12D, a laser driver 1217 is provided, whichdelivers a controlled amount of current at a sufficiently high voltageto operate the laser diodes 1218, 1219 and 1220. Optionally, a bluelaser device 1218, a red laser device 1219 and a green laser device 1220are provided. The laser light emitted by each of the three laser devicesis collected by beam shaping optical elements 1221, such as lenses ormirrors, which direct the light with a preferred direction and beamshape.

In this embodiment, the blue laser device 1218, the red laser device1219 and the green laser device 1220 are provided and form the basis forthree independently controllable color “channels”. A laser driver 1217is provided which powers the laser devices and is configured such thatthe three laser devices are individually addressable and can be poweredindependently of the rest. In some embodiments, one or more beam shapingoptical elements 1221 is provided in order to shape or focus the whitelight spectrum from the wavelength converting element. The beam shapingoptical elements 1221 may also be configured to combine the red, greenand blue laser light into a single beam with similar divergence anddirection of propagation. Optionally, a plurality of laser diodes ofeach color may be used.

In an embodiment with multiple lasers in any of the color channels theplurality of lasers may be powered collectively, independently or may beconfigured such that a subset of the devices are powered collectivelywhile another subset are individually addressable by the laser driver.In an example, a laser light engine contains a red, green and blue colorchannel provided by red, green and blue laser diodes, respectively. Theblue channel, for example, is comprised by 4 blue laser diodes withcenter wavelengths of 420, 450, 450 and 480 nm. The 420 and 480 rundevices are individually addressable by the laser driver and the two 450nm devices are collectively addressable by the driver, i.e. they cannotbe operated independently of one another a different power levels. Sucha configuration results in individually controllable “sub channels”,which are advantageous for several reasons. Firstly, relativeintensities of lasers with varying wavelength may be adjusted to producea spectrum with a desired color point, such that the color gamut of thelight engine is larger than that achievable with a single red, green andblue source. Secondly, different wavelengths of light have been shown tohave an effect on the health and function of the human body. In anexample application, the ratio of short wavelength to long wavelengthblue light could be adjusted by individually controlling the blue lasersources throughout a day so as to limit interference with the naturalcircadian rhythm due to exposure to short wavelength light at night.

According to an embodiment, the present invention provides a lightengine with no wavelength converting element, that can function as awhite light source for general lighting applications as well as displaysand also as an emitter for visible light communication. The emitterconsists of three or more laser or SLED light sources. At least onelight source emits a spectrum with a center wavelength in the range of420-480 nm and acts as a blue light source. At least one light emits aspectrum with a center wavelength in the range of 480-550 nm and acts asa green light source. At least one light emits a spectrum with a centerwavelength in the range 600-670 nm and acts as a red light source. Thelight engine also contains one or more laser or SLED light sourcesemitting at non-visible wavelengths longer than 700 nm. Each lightsource is individually addressable, such that they may be operatedindependently of one another and act as independent communicationchannels, or in the case of multiple emitters in the red, green or bluewavelength ranges the plurality of light sources in each range may beaddressed collectively, though the plurality of sources in each rangeare addressable independently of the sources in the other wavelengthranges. The non-visible light sources are also individually addressableas a group independently from the light sources of the red, green andblue wavelength ranges, and can be used to transmit data at wavelengthsthat are not visible to the human eye. In an example, the non-visiblelasers or SLEDs may emit at typical telecommunication wavelengths suchas between 1.3 and 1.55 microns. In another example, the non-visiblelasers or SLEDs may emit spectra with center wavelengths between 800 nmand 1.3 microns. This embodiment functions as a light source withtunable color, allowing for a plurality of combinations of red, greenand blue light as well as data transmission at non-visible wavelengths.

According to an embodiment, the present invention provides a lightengine with no wavelength converting element, that can function as awhite light source for general lighting applications as well as displaysand also as an emitter for visible light communication. The emitterconsists of three or more laser or SLED light sources. At least onelight source emits a spectrum with a center wavelength in the range of420-480 nm and acts as a blue light source. At least one light emits aspectrum with a center wavelength in the range of 480-550 nm and acts asa green light source. At least one light emits a spectrum with a centerwavelength in the range 600-670 nm and acts as a red light source. Eachlight source is individually addressable, such that they may be operatedindependently of one another and act as independent communicationchannels, or in the case of multiple emitters in the red, green or bluewavelength ranges the plurality of light sources in each range may beaddressed collectively, though the plurality of sources in each rangeare addressable independently of the sources in the other wavelengthranges. This embodiment functions as a light source with tunable color,allowing for a plurality of combinations of red, green and blue lightwith data transmission capability using one or more of the laserdevices. In several preferred embodiments, diffuser elements could beused to reduce the coherence and collimation of the laser light source.

In some embodiments, the light engine is provided with a plurality ofblue or violet pump lasers which are incident on a first surface of thewavelength converting element. The plurality of blue or violet pumplasers is configured such that each pump laser illuminates a differentregion of the first surface of the wavelength converting element. In aspecific embodiment, the regions illuminated by the pump lasers are notoverlapping. In a specific embodiment, the regions illuminated by thepump lasers are partially overlapping. In a specific embodiment, asubset of pump lasers illuminate fully overlapping regions of the firstsurface of the wavelength converting element while one or more otherpump lasers are configured to illuminate either a non-overlapping orpartially overlapping region of the first surface of the wavelengthconverting element. Such a configuration is advantageous because bydriving the pump lasers independently of one another the size and shapeof the resulting light source can by dynamically modified such that theresulting spot of white light once projected through appropriate opticalelements can by dynamically configured to have different sizes andshapes without the need for a moving mechanism.

In an alternative embodiment, the laser or SLED pump light sources andthe wavelength converting element are contained in a sealed packageprovided with an aperture to allow the white light spectrum to beemitted from the package. In specific embodiments, the aperture iscovered or sealed by a transparent material, though in some embodimentsthe aperture may be unsealed. In an example, the package is a TOcanister with a window that transmits all or some of the pump anddown-converted light. In an example, the package is a TO canister with awindow that transmits all or some of the pump and down-converted light.

FIG. 13A is a schematic diagram of a laser based white light sourceoperating in transmission mode and housed in a TO style packageaccording to an embodiment of the present invention. Referring to FIG.13A, the TO-can package includes a base member 1001, a shaped pedestal1005 and pins 1002. The base member 1001 can be comprised of a metalsuch as copper, copper tungsten, aluminum, or steel, or other. The pins1002 are either grounded to the base or are electrically insulated fromit and provide a means of electrically accessing the laser device. Thepedestal member 1005 is configured to transmit heat from the pedestal tothe base member 1001 where the heat is subsequently passed to a heatsink. A cap member 1006 is provided with a window 1007 hermeticallysealed. The cap member 1006 itself also is hermetically sealed to thebase member 1001 to enclose the laser based white light source in the TOpackage.

A laser device 1003 is provided to be mounted on the pedestal 1005 in aCPoS package such that its emitting facet is aimed at a wavelengthconverting element 1004. The mounting to the pedestal can beaccomplished using a soldering or gluing technique such as using AuSnsolders, SAC solders such as SAC305, lead containing solder, or indium,but can be others. In an alternative embodiment sintered Ag pastes orfilms can be used for the attach process at the interface. Sintered Agattach material can be dispensed or deposited using standard processingequipment and cycle temperatures with the added benefit of higherthermal conductivity and improved electrical conductivity. For example,AuSn has a thermal conductivity of about 50 W/m-K and electricalconductivity of about 16 μΩcm whereas pressureless sintered Ag can havea thermal conductivity of about 125 W/m-K and electrical conductivity ofabout 4 μΩcm, or pressured sintered Ag can have a thermal conductivityof about 250 W/m-K and electrical conductivity of about 2.5 μΩcm. Due tothe extreme change in melt temperature from paste to sintered form, (260C-900 C), processes can avoid thermal load restrictions on downstreamprocesses, allowing completed devices to have very good and consistentbonds throughout. Electrical connections from the p-electrode andn-electrode of the laser diode are made using wire bonds 1008 whichconnect to the pins 1002. The pins are then electrically coupled to apower source to electrify the white light source and generate whitelight emission. In this configuration the white light source is notcapped or sealed such that is exposed to the open environment.

The laser light emitted from the laser device 1003 shines through thewavelength converting element 1004 and is either fully or partiallyconverted to longer wavelength light. The down-converted light andremaining laser light is then emitted from the wavelength convertingelement 1004. The CPoS packaged white light source configured in a cantype package as shown in FIG. 13A includes an additional cap member 1006to form a sealed structure around the white light source on the basemember 1001. The cap member 1006 can be soldered, brazed, welded, orglue to the base. The cap member 1006 has a transparent window 1007configured to allow the emitted white light to pass to the outsideenvironment where it can be harnessed in application. The sealing typecan be an environmental seal or a hermetic seal, and in an example thesealed package is backfilled with a nitrogen gas or a combination of anitrogen gas and an oxygen gas. Optionally, the window 1007 and capmember 1006 are joined using epoxy, glue, metal solder, glass fritsealing and friction welding among other bonding techniques appropriatefor the window material. Optionally, the cap member 1006 is eithercrimped onto the header of the base member 1001 or sealed in place usingepoxy, glue, metal solder, glass fit sealing and friction welding amongother bonding techniques appropriate for the cap material such that ahermetic seal is formed.

The laser devices are configured such that they illuminate thewavelength converting element 1004 and any non-converted pump light istransmitted through the wavelength converting element 1004 and exits thecanister through the window 1007 of the cap member 1006. Down-convertedlight emitted by the wavelength converting element is similarly emittedfrom the TO canister through the window 1007.

In an embodiment, the CPoS light source package is a TO canister with awindow that transmits all or some of the pump and down-converted lightand the wavelength converting element is illuminated in a reflectionmode. FIG. 13B is a schematic diagram of a laser based white lightsource operating in reflection mode and housed in a TO style packageaccording to another embodiment of the present invention. The canisterbase consists of a header 1106, wedge shaped member 1102 andelectrically isolated pins that pass-through the header. The laserdevices 1101 and the wavelength converting element 1105 are mounted tothe wedge shaped member 1102 and pedestal, respectively, using athermally conductive bonding media such as silver epoxy or with a soldermaterial, preferably chosen from one or more of AuSn, AgCuSn, PbSn, orIn. The package is sealed with a cap 1103 which is fitted with atransparent window 1104. The window 1104 and cap 1103 are joined usingepoxy, glue, metal solder, glass frit sealing and friction welding amongother bonding techniques appropriate for the window material. The cap1103 is either crimped onto the header 1106 or sealed in place usingepoxy, glue, metal solder, glass frit sealing and friction welding amongother bonding techniques appropriate for the cap material such that ahermetic seal is formed. The laser devices are configured such that theyilluminate the wavelength converting element 1105 and any non-convertedpump light is reflected or scattered from the wavelength convertingelement 1105 and exits the canister through the cap window 1104.Down-converted light emitted by the wavelength converting element 1105is similarly emitted from the canister through the window 1104.

In another embodiment, a reflective mode integrated white light sourceis configured in a flat type package with a lens member to create acollimated white beam as illustrated in FIG. 13C. Referring to the FIG.13C, the flat type package has a base or housing member 1301 with acollimated white light source 1302 mounted to the base and configured tocreate a collimated white beam to exit a window 1303 configured in theside of the base or housing member. The mounting to the base or housingcan be accomplished using a soldering or gluing technique such as usingAuSn solders, SAC solders such as SAC305, lead containing solder, orindium, but can be others. In an alternative embodiment sintered Agpastes or films can be used for the attach process at the interface.Sintered Ag attach material can be dispensed or deposited using standardprocessing equipment and cycle temperatures with the added benefit ofhigher thermal conductivity and improved electrical conductivity. Forexample, AuSn has a thermal conductivity of about 50 W/m-K andelectrical conductivity of about 16 μΩcm whereas pressureless sinteredAg can have a thermal conductivity of about 125 W/m-K and electricalconductivity of about 4 μΩcm, or pressured sintered Ag can have athermal conductivity of about 250 W/m-K and electrical conductivity ofabout 2.5 μΩcm. Due to the extreme change in melt temperature from pasteto sintered form, (260° C.-900° C.), processes can avoid thermal loadrestrictions on downstream processes, allowing completed devices to havevery good and consistent bonds throughout. Electrical connections to thewhite light source can be made with wire bonds to the feedthroughs 1304that are electrically coupled to external pins 1305. In this example,the collimated reflective mode white light source 1302 comprises thelaser diode 1306, the phosphor wavelength converter 1307 configured toaccept the laser beam, and a collimating lens such as an aspheric lens1308 configured in front of the phosphor to collect the emitted whitelight and form a collimated beam. The collimated beam is directed towardthe window 1303 wherein the window region is formed from a transparentmaterial. The transparent material can be a glass, quartz, sapphire,silicon carbide, diamond, plastic, or any suitable transparent material.The external pins 1305 are electrically coupled to a power source toelectrify the white light source and generate white light emission. Asseen in the FIG. 13C, any number of pins can be included on the flatpack. In this example there are 6 pins and a typical laser diode driveronly requires 2 pins, one for the anode and one for the cathode. Thus,the extra pins can be used for additional elements such as safetyfeatures like photodiodes or thermistors to monitor and help controltemperature. Of course, FIG. 13C is merely an example and is intended toillustrate one possible configuration of sealing a white light source.

In one embodiment according to the present invention, a transmissivemode integrated white light source is configured in a flat type packagewith a lens member to create a collimated white beam as illustrated inFIG. 13D. Referring to the FIG. 13D, the flat type package has a base orhousing member 1311 with a collimated white light source 1312 mounted tothe base and configured to create a collimated white beam to exit awindow 1313 configured in the side of the base or housing member. Themounting to the base or housing can be accomplished using a soldering orgluing technique such as using AuSn solders, SAC solders such as SAC305,lead containing solder, or indium, but can be others. In an alternativeembodiment sintered Ag pastes or films can be used for the attachprocess at the interface. Sintered Ag attach material can be dispensedor deposited using standard processing equipment and cycle temperatureswith the added benefit of higher thermal conductivity and improvedelectrical conductivity. For example, AuSn has a thermal conductivity ofabout 50 W/m-K and electrical conductivity of about 16 μΩcm whereaspressureless sintered Ag can have a thermal conductivity of about 125W/m-K and electrical conductivity of about 4 μΩcm, or pressured sinteredAg can have a thermal conductivity of about 250 W/m-K and electricalconductivity of about 2.5 μΩcm. Due to the extreme change in melttemperature from paste to sintered form, (260° C.-900° C.), processescan avoid thermal load restrictions on downstream processes, allowingcompleted devices to have very good and consistent bonds throughout.Electrical connections to the white light source can be made with wirebonds to the feedthroughs 1313 that are electrically coupled to externalpins 1314. In this example, the collimated transmissive mode white lightsource 1312 comprises the laser diode 1316, the phosphor wavelengthconverter 1317 configured to accept the laser beam, and a collimatinglens such as an aspheric lens 1318 configured in front of the phosphorto collect the emitted white light and form a collimated beam. Thecollimated beam is directed toward the window 1315 wherein the windowregion is formed from a transparent material. The transparent materialcan be a glass, quartz, sapphire, silicon carbide, diamond, plastic, orany suitable transparent material. The external pins 1314 areelectrically coupled to a power source to electrify the white lightsource and generate white light emission. Referring to the FIG. 13D, anynumber of pins can be included on the flat pack. In this example thereare 6 pins and a typical laser diode driver only requires 2 pins, onefor the anode and one for the cathode. Thus, the extra pins can be usedfor additional elements such as safety features like photodiodes orthermistors to monitor and help control temperature. Of course, FIG. 13Dis merely an example and is intended to illustrate one possibleconfiguration of sealing a white light source.

In another example, the package can be in a butterfly package type. Thebutterfly package can either have a window provided in one or more ofsides, bottom, and top which transmits the pump and down-convertedlight. In another example, the laser or SLED pump light source isco-packaged on a common substrate along with the wavelength convertingelement. A shaped member may be provided separating either the pumplight source or the wavelength converting element from the commonsubstrate such that the pump light is incident on the wavelengthconverting element at some angles which is not parallel to the surfacenormal of the wavelength covering member. The package can also containother optical, mechanical and electrical elements. In a specificembodiment, the butterfly package contains lenses for collimating thelight emitted by the one or more laser devices. In a specificembodiment, the butterfly package contains one or more MEMS mirrorscapable of rotating in one or more axes for directing the laser light.

There are several configurations that enable a remote pumping ofphosphor material using one or more laser diode excitation sources. Inan embodiment one or more laser diodes are remotely coupled to one ormore phosphor members with a free-space optics configuration. That is,at least part of the optical path from the emission of the laser diodeto the phosphor member is comprised of a free-space optics setup. Insuch a free-space optics configuration the optical beam from the laserdiode may be shaped using optical elements such as collimating lensincluding a fast axis collimator, slow axis collimator, aspheric lens,ball lens, or other elements such as glass rods. In other embodiments ofa free-space optical pumping the beam may not be shaped and simplydirectly coupled to the phosphor. In another embodiment a waveguideelement is used to couple the optical excitation power from the one ormore laser diodes to the phosphor member. The waveguide element includesone or more materials selected from Si, SiN, GaN, GaInP, Oxides, orothers.

In another embodiment, an optical fiber is used as the waveguide elementwherein on one end of the fiber the electromagnetic radiation from theone or more laser diodes is in-coupled to enter the fiber and on theother end of the fiber the electromagnetic radiation is out-coupled toexit the fiber wherein it is then incident on the phosphor member. Theoptical fiber could be comprised of a glass material such as silica, apolymer material, or other, and could have a length ranging from 100 μmto about 100 m or greater.

In alternative examples, the waveguide element could consist of glassrods, optical elements, specialized waveguide architectures

FIG. 14 is a simplified diagram illustrating a front view of a laserdevice with multiple cavity members. Referring to FIG. 14, an activeregion 1407 can be seen as positioned in the substrate 1401. The cavitymember 1402 as shown includes a via 306. Vias are provided on the cavitymembers and opened in a dielectric layer 1403, such as silicon dioxide.The top of the cavity members with vias can be seen as laser ridges,which expose electrode 1404 for an electrical contact. The electrode1404 includes p-type electrode. In a specific embodiment, a commonp-type electrode is deposited over the cavity members and dielectriclayer 1403.

The cavity members are electrically coupled to each other by theelectrode 1404. The laser diodes, each having an electrical contactthrough its cavity member, share a common n-side electrode. Depending onthe application, the n-side electrode can be electrically coupled to thecavity members in different configurations. In a preferred embodiment,the common n-side electrode is electrically coupled to the bottom sideof the substrate. In certain embodiments, n-contact is on the top of thesubstrate, and the connection is formed by etching deep down into thesubstrate from the top and then depositing metal contacts. For example,laser diodes are electrically coupled to one another in a parallelconfiguration. In this configuration, when current is applied to theelectrodes, all laser cavities can be pumped relatively equally.Further, since the ridge widths will be relatively narrow in the 1.0 to5.0 μm range, the center of the cavity member will be in close vicinityto the edges of the ridge (e.g., via) such that current crowding ornon-uniform injection will be mitigated.

It is to be appreciated that the laser device with multiple cavitymembers has an effective ridge width of n×w, which could easily approachthe width of conventional high power lasers having a width in the 10 to50 μm range. Typical lengths of this multi-stripe laser could range from400 μm to 2000 μm, but could be as much as 3000 μm. The laser deviceillustrated in FIG. 14 has a wide range of applications. For example,the laser device can be coupled to a power source and operate at a powerlevel of 0.5 to 10 W. In certain applications, the power source isspecifically configured to operate at a power level of greater than 10W. The operating voltage of the laser device can be less than 5 V, 5.5V, 6 V, 6.5 V, 7 V, and other voltages. In various embodiments, the wallplug efficiency (e.g., total electrical-to-optical power efficiency) canbe 15% or greater, 20% or greater, 25% or greater, 30% or greater, 35%or greater.

FIG. 15 is a simplified diagram illustrating an individually addressablelaser package according to an embodiment of the present invention. Thelaser bar includes a number of emitters separated by ridge structures.Each of the emitter is characterized by a width of about 90-200 μm, butit is to be understood that other dimensions are possible as well. Eachof the laser emitters includes a pad for p-contact wire bond. Forexample, electrodes can be individually coupled to the emitters so thatit is possible to selectively turning a emitter on and off. Theindividually addressable configuration shown in the FIG. 15 providesnumerous benefits. For example, if a laser bar having multiple emittersis not individually addressable, laser bar yield during manufacturingcan be a problem, since many individual laser devices need to be good inorder for the bar to pass, and that means laser bar yield will be lowerthan individual emitter yield. In addition, setting up the laser barwith single emitter addressability makes it possible to screen eachemitter. In a certain embodiments, a control module is electricallycoupled to the laser for individually controlling devices of the laserbar.

FIG. 16 is a simplified diagram illustrating laser bars configured withan optical combiner according to embodiments of the present invention.As shown, the diagram includes a package or enclosure for multipleemitters. Each of the devices is configured on a single ceramic ormultiple chips on a ceramic, which are disposed on common heat sink. Asshown, the package includes all free optics coupling, collimators,mirrors, spatially or polarization multiplexed for free space output orrefocused in a fiber or other waveguide medium. As an example, thepackage has a low profile and may include a flat pack ceramic multilayeror single layer. The layer may include a copper, a copper tungsten basesuch as butterfly package or covered CT mount, Q-mount, or others. In aspecific embodiment, the laser devices are soldered on CTE matchedmaterial with low thermal resistance (e.g., AlN, diamond, diamondcompound) and forms a sub-assembled chip on ceramics. The sub-assembledchip is then assembled together on a second material with low thermalresistance such as copper including, for example, active cooling (i.e.,simple water channels or micro channels), or forming directly the baseof the package equipped with all connections such as pins. The flatpackis equipped with an optical interface such as window, free space optics,connector or fiber to guide the light generated and a coverenvironmentally protective.

FIG. 17 is an example of a free-space mirror based laser combiner.Individual laser beams are first collimated through free-space opticssuch as fast axis collimating (FAC) and slow axis collimating (SAC)lenses. Next the collimated laser beams are incident on turning mirrorsto change the direction of the laser beams by 90 degrees. This is donefor an array of laser diode beams which are combined into one singlebeam and then coupled into the light guide such as a fiber.

FIG. 18A is an example of enclosed free space laser module. A case 1800is used for assembling the free-space mirror based laser combiner ofFIG. 17. The laser module includes two electrical supply pins 1810 forproviding driving voltages for the laser diodes. The case 1800 includesa hole for a fiber to couple with the light guide output combined fromall laser diodes through the series of mirrors. An access lid 1820 isdesigned for easy access of optical elements in the assembly. A compactplug-and-play design provides a lot of flexibilities and ease of use.

FIG. 18B is a schematic of an enclosed free space multi-chip lasermodule with an extended delivery fiber plus phosphor converter accordingto an example of the present invention. As shown, the enclosed freespace multi-chip laser module is substantially similar to the one shownin FIG. 18A to produce a laser light beam in violet or blue lightspectrum. The multiple laser chips in the package provide substantiallyhigh intensity for the light source that is desired for many newapplications. Additionally, an extended optical fiber with one end iscoupled with the light guide output for further guiding the laser lightbeam to a desired distance for certain applications up to 100 m orgreater. Optionally, the optical fiber can be also replaced by multiplewaveguides built in a planar structure for adapting silicon photonicsintegration. At the other end of the optical fiber, a phosphor materialbased wavelength converter may be disposed to receive the laser light,where the violet or blue color laser light is converted to white colorlight and emitted out through an aperture or collimation device. As aresult, a white light source with small size, remote pump, and flexiblesetup is provided.

In another example, the package is a custom package made from one ormore of plastic, metal, ceramics and composites.

In another embodiment, the laser devices are co-packaged on a commonsubstrate along with the wavelength converting element. A shaped membermay be provided separating either the laser devices or the wavelengthconverting element from the common substrate such that the pump light isincident on the wavelength converting element at some angle which is notparallel to the surface normal of the wavelength covering member.Transmission mode configurations are possible, where the laser light isincident on a side of the wavelength converting element not facing thepackage aperture. The package can also contain other optical, mechanicaland electrical elements.

In an embodiment, the common substrate is a solid material with thermalconductivity greater than 100 W/m-K. In an example, the common substrateis preferably a solid material with thermal conductivity greater than200 W/m-K. In an example, the common substrate is preferably a solidmaterial with thermal conductivity greater than 400 W/m-K. In anexample, the common substrate is preferably a solid material withelectrical insulator with electrical resistivity greater than 1×10⁶ Ωcm.In an example, the common substrate is preferably a solid material withthin film material providing electrical 1×10⁶ Ωcm. In an example, thecommon substrate selected from one or more of Al₂O₃, AlN, SiC, BeO anddiamond. In an example, the common substrate is preferably comprised ofcrystalline SiC. In an example, the common substrate is preferablycomprised of crystalline SiC with a thin film of Si₃N₄ deposited ontothe top surface. In an example, the common substrate contains metaltraces providing electrically conductive connections between the one ormore low-cost laser diodes. In an example, the common substrate containsmetal traces providing thermally conductive connections between the oneor more low-cost laser diodes and the common substrate.

In an embodiment, the common substrate is a composite structurecomprised by a plurality or layers or regions of differing compositionor electrical conductivity. In an example, the common substrate is ametal-core printed circuit board comprised by a core layer of aluminumor copper surrounded by layers of insulating plastic. Through vias,solder masks and solder pads may be provided. In an example, the commonsubstrate is a ceramic substrate comprised by a ceramic core plate cladin patterned metallic pads for bonding and electrical contact. Theceramic substrate may contain metal filled vias for providing electricalcommunication between both faces of the ceramic plate. In an example,the common substrate consists of a metal core or slug surrounded by aninsulating material such as plastic or ceramic. The surroundinginsulating material may contain through vias for electricalcommunication between the front and back faces of the substrate. Theinsulating material may also have metallic or otherwise conducting padspatterned on it for wire-bonding.

In an embodiment, the one or more low-cost laser diodes are attached tothe common substrate with a solder material. In an example, the one ormore low-cost laser diodes are attached to the metal traces on thecommon substrate with a solder material, preferably chosen from one ormore of AuSn, AgCuSn, PbSn, or In.

In an embodiment, the wavelength conversion material is attached to thecommon substrate with a solder material. In an example, the wavelengthconversion material is attached to the metal traces on the commonsubstrate with a solder material, preferably chosen from one or more ofAuSn, AgCuSn, PbSn, or In.

In an example, the wavelength conversion element contains an opticallyreflective material interposed between the wavelength conversion elementand the thermally conductive connection to the common substrate.

In an embodiment, the optically reflective material interposed betweenthe wavelength conversion element and the thermally conductiveconnection to the common substrate has a reflectivity value of greaterthan 50%. In an embodiment the optically reflective material interposedbetween the wavelength conversion element and the thermally conductiveconnection to the common substrate has a reflectivity value of greaterthan 80%. In an example, the optically reflective material interposedbetween the wavelength conversion element and the thermally conductiveconnection to the common substrate has a reflectivity value of greaterthan 90%. In an example, optical beam shaping elements are placedbetween the low-cost laser diodes and the wavelength conversion element.

In an embodiment, the wavelength conversion element contains geometricalfeatures aligned to each of the one or more low-cost laser diodes. In anexample, the wavelength conversion element further contains an opticallyreflective material on the predominate portion of the edgesperpendicular to the common substrate and one or more low-cost laserdiodes, and where the geometrical features aligned to each of thelow-cost laser diodes does not contain an optically reflective material.In an example, the common substrate is optically transparent. In anexample, the wavelength conversion element is partially attached to thetransparent common substrate. In an example, the wavelength convertedlight is directed through the common substrate. In an example, thewavelength converter contains an optically reflective material on atleast the top surface. In an example, the one or more low-cost laserdiodes and the wavelength conversion element are contained within asealing element to reduce the exposure to the ambient environment. In anexample, the one or more low-cost laser diodes and the wavelengthconversion element are contained within a sealing element to reduce theexposure to the ambient environment.

FIG. 19A is a schematic diagram illustrating an off-axis reflective modeembodiment of an integrated laser-phosphor white light source accordingto the present invention. In this embodiment the gallium and nitrogencontaining lift-off and transfer technique is deployed to fabricate avery small and compact submount member with the laser diode chip formedfrom transferred epitaxy layers. Further, in this example the phosphoris tilted with respect to the fast axis of the laser beam at an angleω₁. The laser based white light device is comprised of a support member1401 that serves as the support member for the laser diode CoS 1402formed in transferred gallium and nitrogen containing epitaxial layers1403. The phosphor material 1406 is mounted on a support member 1408wherein the support members 1401 and 1408 would be attached to a commonsupport member such as a surface in a package member such as a surfacemount package. The laser diode or CoS is configured with electrodes 1404and 1405 that may be formed with deposited metal layers and combinationof metal layers including, but not limited to Au, Pd, Pt, Ni, Al, Agtitanium, or others such as transparent conductive oxides such as indiumtin oxide. The laser beam output excites the phosphor material 1406positioned in front of the output laser facet. The electrodes 1404 and1405 are configured for an electrical connection to an external powersource such as a laser driver, a current source, or a voltage source.Wirebonds can be formed on the electrodes to couple electrical power tothe laser diode device to generate a laser beam 1407 output from thelaser diode and incident on the phosphor 1406. Of course this is merelyan example of a configuration and there could be many variants on thisembodiment including but not limited to different shape phosphors,different geometrical designs of the submount, support members,different orientations of the laser output beam with respect to thephosphor, different electrode and electrical designs, and others.

FIG. 19B is a schematic diagram illustrating an off-axis reflective modephosphor with two laser diode devices embodiment of an integratedlaser-phosphor white light source according to the present invention. Inthis embodiment the gallium and nitrogen containing lift-off andtransfer technique is deployed to fabricate a very small and compactsubmount member with the laser diode chip formed from transferredepitaxy layers. Further, in this example the phosphor is tilted withrespect to the fast axis of the laser beam at an angle ω₁. The laserbased white light sources is comprised of two or more laser diodesincluding support members 1401 that serves as the support member for thetwo laser diodes 1402 formed in transferred gallium and nitrogencontaining epitaxial layers 1403. The phosphor material 1406 is mountedon a support member 408 wherein the support members 1401 and 1408 wouldbe attached to a common support member such as a surface in a packagemember such as a surface mount package. The laser diodes or CoS devicesare configured with electrodes 1404 and 1405 that may be formed withdeposited metal layers and combination of metal layers including, butnot limited to Au, Pd, Pt, Ni, Al, Ag titanium, or others such astransparent conductive oxides such as indium tin oxide. The multiplelaser beams 1407 excite the phosphor material 1406 positioned in frontof the output laser facet.

Referring to FIG. 19B the laser diode excitation beams 1407 are rotatedwith respect to each other such that the fast axis of the first beam isaligned with the slow axis of the second beam to form a more circularexcitation spot. The electrodes 1404 and 1405 are configured for anelectrical connection to an external power source such as a laserdriver, a current source, or a voltage source. Wirebonds can be formedon the electrodes to couple electrical power to the laser diode deviceto generate the multiple laser beams 1407 incident on the phosphor 1406.Of course this is merely an example of a configuration and there couldbe many variants on this embodiment including but not limited to morethan two laser diodes such as three of four laser diodes, differentshape phosphors, different geometrical designs of the submount, supportmembers, different orientations of the laser output beam with respect tothe phosphor, wiring the laser diodes in series or parallel, differentelectrode and electrical designs including individually addressablelasers, and others.

FIG. 20A is a schematic diagram of an exemplary laser based white lightsource operating in reflection mode and housed in a surface mountpackage according to an embodiment of the present invention. Referringto FIG. 20A, a reflective mode white light source is configured in asurface mount device (SMD) type package. The SMD package has a commonsupport base member 1601. The reflective mode phosphor member 1602 isattached to the base member 1601. Optionally, an intermediate submountmember may be included between the phosphor member 1602 and the basemember 1601. The laser diode 1603 is mounted on an angled support member1604, wherein the angled support member 1604 is attached to the basemember 1601. The base member 1601 is configured to conduct heat awayfrom the white light source and to a heat sink. The base member 1601 iscomprised of a thermally conductive material such as copper, coppertungsten, aluminum, SiC, steel, diamond, composite diamond, AlN,sapphire, or other metals, ceramics, or semiconductors.

The mounting to the base member 1601 can be accomplished using asoldering or gluing technique such as using AuSn solders, SAC solderssuch as SAC305, lead containing solder, or indium, but can be others.Alternatively, sintered Ag pastes or films can be used for the attachprocess at the interface. Sintered Ag attach material can be dispensedor deposited using standard processing equipment and cycle temperatureswith the added benefit of higher thermal conductivity and improvedelectrical conductivity. For example, AuSn has a thermal conductivity ofabout 50 W/m-K and electrical conductivity of about 16 μΩcm whereaspressureless sintered Ag can have a thermal conductivity of about 125W/m-K and electrical conductivity of about 4 μΩcm, or pressured sinteredAg can have a thermal conductivity of about 250 W/m-K and electricalconductivity of about 2.5 μΩcm. Due to the extreme change in melttemperature from paste to sintered form, 260° C.-900° C., processes canavoid thermal load restrictions on downstream processes, allowingcompleted devices to have very good and consistent bonds throughout. Themounting joint could also be formed from thermally conductive glues,thermal epoxies such as silver epoxy, and other materials.

Electrical connections from the electrodes of the laser diode are madeto using wirebonds 1605 to electrode members 1606. Wirebonds 1607 and1608 are formed to internal feedthroughs 1609 and 1610. The feedthroughsare electrically coupled to external leads. The external leads can beelectrically coupled to a power source to electrify the white lightsource and generate white light emission.

The top surface of the base member 1601 may be comprised of, coatedwith, or filled with a reflective layer to prevent or mitigate anylosses relating from downward directed or reflected light. Moreover, allsurfaces within the package including the laser diode and submountmember may be enhanced for increased reflectivity to help improve theuseful white light output.

In this configuration the white light source is not capped or sealedsuch that is exposed to the open environment. In some examples of thisembodiment of the integrated white light source apparatus, anelectrostatic discharge (ESD) protection element such as a transientvoltage suppression (TVS) element is included. Of course, FIG. 20A ismerely an example and is intended to illustrate one possible simpleconfiguration of a surface mount packaged white light source.Specifically, since surface mount type packages are widely popular forLEDs and other devices and are available off the shelf they could be oneoption for a low cost and highly adaptable solution.

FIG. 20B is an alternative example of a packaged white light sourceincluding 2 laser diode chips according to the present invention. Inthis example, a reflective mode white light source is configured also inthe SMD type package. The SMD package has a base member 1601 with thereflective mode phosphor member 1602 mounted on a support member or on abase member. A first laser diode device 1613 may be mounted on a firstsupport member 1614 or a base member 1601. A second laser diode device1615 may be mounted on a second support member 1616 or a base member1601. The support members and base member are configured to conduct heataway from the phosphor member 1602 and laser diode devices 1613 and1615.

The external leads can be electrically coupled to a power source toelectrify the laser diode sources to emit a first laser beam 1618 fromthe first laser diode device 1613 and a second laser beam 1619 from asecond laser diode device 1615. The laser beams are incident on thephosphor member 1602 to create an excitation spot and a white lightemission. The laser beams are preferably overlapped on the phosphormember 1602 to create an optimized geometry and/or size excitation spot.For example, the laser beams from the first and second laser diodes arerotated by 90 degrees with respect to each other such that the slow axisof the first laser beam 1618 is aligned with the fast axis of the secondlaser beam 1619.

The top surface of the base member 1601 may be comprised of, coatedwith, or filled with a reflective layer to prevent or mitigate anylosses relating from downward directed or reflected light. Moreover, allsurfaces within the package including the laser diode member andsubmount member may be enhanced for increased reflectivity to helpimprove the useful white light output. In this configuration the whitelight source is not capped or sealed such that is exposed to the openenvironment. In some examples of this embodiment of the integrated whitelight source apparatus, an ESD protection element such as a TVS elementis included. Of course, FIG. 20B is merely an example and is intended toillustrate one possible simple configuration of a surface mount packagedwhite light source. Specifically, since surface mount type packages arewidely popular for LEDs and other devices and are available off theshelf they could be one option for a low cost and highly adaptablesolution.

FIG. 20C is an alternative example of a packaged white light sourceaccording to the present invention. In this example, a reflective modewhite light source is configured also in a SMD type package. The SMDpackage has a base member 1601 serving as a common support member for aside-pumped phosphor member 1622 mounted on a submount or support member1623 and a laser diode device 1624 mounted on a submount or supportmember 1625. In some embodiments, the laser diode 1624 and or thephosphor member 1622 may be mounted directly to the base member 1601 ofthe package. The support members and base member 1601 are configured toconduct heat away from the phosphor member 1622 and laser diode device1624. The base member 1601 is substantially the same type as that inFIG. 20A and FIG. 20B in the SMD type package.

Electrical connections from the p-electrode and n-electrode can beelectrically coupled to 1626 and 1627 electrodes on a submount member1625 which would then be coupled to internal feedthroughs in thepackage. The feedthroughs are electrically coupled to external leads.The external leads can be electrically coupled to a power supply sourceto electrify the laser diode and generate a laser beam incident on theside of the phosphor member 1622. The phosphor member 1622 maypreferably be configured for primary white light emission 1628 from thetop surface of the phosphor member 1622. The top surface of the basemember 1601 may be comprised of, coated with, or filled with areflective layer to prevent or mitigate any losses relating fromdownward directed or reflected light. Moreover, all surfaces within thepackage including the laser diode member and submount member may beenhanced for increased reflectivity to help improve the useful whitelight output. In this configuration the white light source is not cappedor sealed such that is exposed to the open environment. In some examplesof this embodiment of the integrated white light source apparatus, anESD protection element such as a TVS element is included. Of course, theexample is FIG. 31e is merely an example and is intended to illustrateone possible simple configuration of a surface mount packaged whitelight source. Specifically, since surface mount type packages are widelypopular for LEDs and other devices and are available off the shelf theycould be one option for a low cost and highly adaptable solution.

The white light sources shown in FIGS. 20A, 20B, and 20C can be enclosedin a number of ways to form a light engine. Optionally, the light engineis encapsulated in a molded epoxy or plastic cover (not shown). Themolded cover may have a flat top or can be molded to have a curved orspherical surface to aid in light extraction. It is possible for thecover to be pre-molded and glued in place, or to be molded in place fromliquid or gel precursors. Because a polymer cover or moldedencapsulating material may absorb laser light or down converted lightfrom the wavelength converting element there is a large risk that theencapsulating material will age due to heating and light absorption.When such a material ages, it tends to become more optically absorbing,leading to a runaway process that inevitably leads to device failure. Ina laser based device, where the laser devices emit light with a veryhigh brightness and optical flux, this aging effect is expected to bequite severe. It is preferred, then, for a polymer cover to be absentfrom the region near the emitting facets of the lasers as well as fromthe path of the laser beams between the laser devices and the wavelengthconverting element. Optionally, the molded cover does not contact thelaser device nor the wavelength converting element nor does it intersectthe laser light beams prior to their intersecting the wavelengthconverting element. Optionally, the molded cover overlays and is incontact with a part or majority of the laser devices and the wavelengthconverting element, but does not cover the emitting facet of the lasersnor the surface of the wavelength converting element, nor does itintersect the beam path of the laser light between the laser devices andthe wavelength converting element. Optionally, the encapsulatingmaterial is molded over the device after wire bonding of the laserdevices, and no air gaps or voids are included.

In another embodiment, the light engine is encapsulated using a rigid,member such as a ceramic or metal housing. For example, a stamped metalwall could be provided with dimensions close to those of the outer edgeof the common substrate. The wall could be attached to the commonsubstrate and an airtight seal formed using epoxy or another glue, metalsolder, glass frit sealing and friction welding among other bondingtechniques. The top edge of the wall could, for example, be sealed byattaching a transparent cover. The transparent cover may be composed ofany transparent material, including silica-containing glass, sapphire,spinel, plastic, diamond and other various minerals. The cover may beattached to the wall using epoxy, glue, metal solder, glass frit sealingand friction welding among other bonding techniques appropriate for thecover material.

In some embodiments the enclosure may be fabricated directly on thecommon substrate using standard lithographic techniques similar to thoseused in processing of MEMS devices. Many light emitters such as laserdiodes could be fabricated on the same common substrate and, oncefabrication is complete, singulated in to separate devices using sawing,laser scribing or a like process.

Identified as a critical sensor technology within the current thrust forautonomous and semi-autonomous operation of devices, vehicles and otherobjects, LIDAR (Light Imaging Detection And Ranging) technology israpidly gaining use in applications where physical surroundings andtopology must be surveyed or actively monitored with high resolution andfast refresh rate. The technology is based on a rather simple method tomeasure the distance to a target or object by directing laser light suchas a pulse of laser light on the target and then measuring the time ittakes for the light to be reflected and returned to the system usingdetection. LIDAR is popularly used to make high-resolution maps forapplications such as geomatics, archaeology, geography, geology,forestry, atmospheric physics, laser guidance, airborne laser swathmapping (ALSM), and laser altimetry.

More recently, LIDAR has become a critical sensor technology forautonomous vehicles such as cars and drones. To enable the split-seconddecision-making needed for self-driving cars, the LIDAR system providesaccurate 3D information on the surrounding environment. Using this data,the processor implements object identification, motion vectordetermination, collision prediction, and avoidance strategies. The LIDARunit is well-suited to imaging, and can provide a 360° view by using arotating system, a scanning mirror system, pr a multiple sensorassembly. High-speed and high-power laser pulses that are timed with theresponses of a detector to calculate the distances to an object from thereflected light. An array of detectors, or a timed camera, can be usedto increase the resolution of the 3D information. The pulse is veryshort to enhance depth resolution, and the resulting light reflectionsare used to create a 3D point-like “cloud” that is analyzed to transformthe data into volume identification and vector information. Thetransformed result is then used to calculate the vehicles' position,speed, and direction relative to these external objects, to determinethe probability of collision, and instruct appropriate action, ifneeded.

The most commonly used methods employed today are Continuous Wave (CW)laser with phase comparison and pulsed laser. CW laser systems operateon the principle that the target object reflects a phase shifted versionof the original transmitted signal. A phase comparator in the receivercompares the phase shifted version of the received signal with theoriginal signal. The phase comparator output can be used to computedistance. A pulsed laser system, as the name suggests, transmits andreceives short, light pulses. Semiconductor pulsed lasers are used forapplications requiring low cost, low power consumption small size, andlight weight. This methodology requires a very fast sampling analog todigital conversion (ADC) in the receiver and is the most common methodin use. The distance that can be measured depends on several factors:the peak power of the laser, the laser beam divergence, optics and airtransmittance, target reflectivity, and the sensitivity of the detector.Transmittance and reflectance parameters are usually imposed by theapplication. Design flexibility resides mainly in the selection of thelaser source (power) and the receiver (sensitivity). The accuracy of TOFmeasurements depends on the pulse width of the laser and the speed andaccuracy of the ADC used. Depending on the application requirements,lasers in the order of a few milliwatts to several hundred Watts areused. The range equation gives the range of a semiconductor pulsed laserbased on its power in Watts and the other system and atmosphericconditions. Certain physical properties of the target can be determinedby the change in wavelength of the reflected light pulse, known as theDoppler shift. To measure the change in wavelength of narrow pulses,ADCs with sample rates in the order of 1 GHz or higher are required.(LIDAR System Design for Automotive/Industrial/Military Applications,Texas Instruments).

According to the present invention, the LIDAR system is configured in adevice, machine, or mobile machine that includes a laser basedillumination source, which could be a laser based smart light describedin this invention. The LIDAR systems according to this invention couldbe supplemented by and/or coupled to other sensors, actuators, andsystems including a GPS (Global Positioning System) receiver serving asa primary subsystem for navigation and guidance. A GPS system typicallycomputes a present position based on complex analysis of signalsreceived from at least four of the constellation of over 60 low-orbitsatellites. A GPS guidance system can be supplemented by inertialguidance which requires no external signal, but rather utilizes aninertial measurement unit (IMU) consisting of a platform fixed to thevehicle or mobile machine. The platform typically has three gyroscopesand three accelerometers, one pair oriented each for of the orthogonalX, Y, and Z axes. These sensors provide data on the rotational andlinear motion of the platform, which then is used to calculate motionand position regardless of speed or any sort of signal obstruction.LIDAR systems are often supplemented by radar for close proximity objector obstacle sensing. Radar (radio detection and ranging) is the masterof motion measurement and uses radio waves to determine the velocity,range and angle of objects. Radar is computationally lighter than a thana Lidar system and although it is less angularly accurate than LIDAR, itcan work in every condition and even use reflection to see behindobstacles. Radar can be used for redundancy to LIDAR. Additionally,camera systems are included with the LIDAR system. Cameras are bestsuited for classification and texture interpretation. They are by farthe cheapest and most available sensor, but they use massive amounts ofdata, making processing a computational intense and algorithmicallycomplex job. Unlike both LIDAR and radar, cameras can see color, makingthem the best for scene interpretation. Of course, any configuration ofsuch subsystems can be included according to the present invention. Tooperate such subsystems individually or in an integrated configurationsophisticated algorithm, and powerful processors to execute software arepreferably included.

The present invention offers strong benefits over previous LIDARtechnologies by including a laser based illumination source, which couldbe a smart laser light source including spatial dynamic function,dynamic color or brightness, and/or visible light communication [VLC]such as LiFi. By combining laser based illumination systems with LIDAR,the LIDAR system can offer increased functionality, increasedsensitivity, smaller or more compact size, improved styling of theapparatus it is included within such as an automobile, improvedintegration in the apparatus it is included within such as anautomobile, and lower cost.

For many 3D sensing LIDAR applications, a scanning laser beam orexpanded laser beam and time of flight measurement can be used to allowdepth coordinate for each pixel. Another approach is to illuminate theentire field with a pulse of light, and use time of flight measurementto gather the depth coordinate in parallel, one frame at a time. Throughthe use of a detector array such as a photodiode array, CCD, antennaarray, CMOS array, or other parallel detection apparatus, this approachenables rapid imaging of the surrounding environment. In many cases,this is done in the infrared, for example 905 nm, 1000 nm, 1064 nm, or1550 nm. These wavelengths have been chosen in order to minimizescattering which increases with shorter wavelength, for eye-safety, toavoid visible light scanning on the object being imaged, and in order toutilize mature laser diodes technology which can be cost effective,reliable, and efficient.

Although infrared sources have been the conventional wavelength employedin LIDAR systems, LIDAR is compatible with a wide source and detectionwavelength range where it finds unique benefits and trade-offs withindifferent wavelength ranges from the ultraviolet to the visible and tothe near and far infrared. Depending on the atmosphere or mediummaterial that the laser light must travel through along with the objectsor terrain being mapped, certain wavelengths or groups of wavelengthsmay be ideal. For example, the LIDAR sensing wavelengths may be selectedfrom a laser source operating with a wavelength of about 10 um all theway into the ultra-violet (UV) in the 250 nm range, or even shorter. Infact, in recent years cost effective, reliable, and efficient galliumand nitrogen containing laser diodes (i.e., GaN laser diodes) operatingin the blue and violet range have emerged, along with high luminance GaNlaser diode pumped phosphor white light sources described throughoutthis invention. Utilizing these visible light sources has severalbenefits such as reduced absorption in water.

Typically the transmitted source light is reflected through abackscattering process and is then detected by the LIDAR system. Themost common backscattering processes used for LIDAR systems includeRayleigh scattering, Mie scattering, Raman scattering, and fluorescence,all of which can be utilized in the present invention. Based ondifferent kinds of backscattering, the LIDAR can be accordingly calledRayleigh LIDAR, Mie LIDAR, Raman LIDAR, and so on. Suitable combinationsof wavelengths can allow for remote mapping of atmospheric contents byidentifying wavelength-dependent changes in the intensity of thereturned signal.

Rayleigh scattering is the elastic scattering of light or otherelectromagnetic radiation by particles much smaller than the wavelengthof the radiation and does not change the state of material. Theparticles may be individual atoms or molecules and can occur when lighttravels through transparent solids and liquids, but is most prominentlyseen in gases. While Rayleigh scattering refers primarily to the elasticscattering of light from atomic and molecular particles whose diameteris less than about one-tenth the wavelength of the incident light, Miescattering refers primarily to the elastic scattering of light fromatomic and molecular particles whose diameter is larger than about thewavelength of the incident light. In Mie scattering all wavelengths ofwhite light are scattered approximately equally and since largeparticles in the atmosphere are able to scatter all wavelengths of whitelight equally clouds appear white. Raman scattering is inelasticscattering of light from objects whereby the scattered photon has alower (Raman Stokes scattering) or higher (Raman anti-Stokes scattering)energy than the incident photon. In certain embodiments of the presentinvention LIDAR systems contain suitable combinations of sensingwavelengths to allowing for remote mapping of atmospheric contents byidentifying wavelength-dependent changes in the intensity of thereturned signal.

LIDAR can spatially map a wide range of materials, including buildings,structures, humans and animals, vehicles, objects, rocks, rain, chemicalcompounds, aerosols, clouds and even single molecules. In fact, aircraftbased LIDAR systems have been shown to map down to a cm resolution.LIDAR instruments fitted to aircraft and satellites carry out surveyingand mapping—a recent example being the U.S. Geological SurveyExperimental Advanced Airborne Research Lidar. NASA has identified LIDARas a key technology for enabling autonomous precision safe landing offuture robotic and crewed lunar-landing vehicles. LIDAR is gainingwidespread acceptance as the critical sensor technology for autonomousdevices such as autonomous vehicles.

According to this invention combining LIDAR and gallium and nitrogencontaining laser diodes, two kinds of LIDAR detection schemes can bedeployed: “incoherent” or direct energy time of flight detection(primarily an amplitude measurement) and coherent detection (Doppler orphase sensitive measurements). Coherent systems generally use opticalheterodyne detection, which, being more sensitive than direct detection,allows them to operate at a much lower power but at the expense of morecomplex transceiver requirements.

In both coherent and incoherent LIDAR the micropulse LIDAR pulse systemor high energy pulse system can be deployed for spatial mapping.Micropulse systems have developed based on the vast computer poweravailability combined with advances in laser technology. They useconsiderably less energy in the laser, typically on the order of onemicrojoule, and are often “eye-safe,” meaning they can be used withoutsafety precautions. High-power systems are common in atmosphericresearch, where they are widely used for measuring many atmosphericparameters.

FIG. 21 presents a simplified version of an existing LIDAR system. Apower source 2701 is configured to supply power to the variouscomponents within the system. The control unit and/or processor 2702 isthe central computing or brains of the system that is responsible fordictating the modulation signal or pulsed signal to a laser driver 2703,dictating the modulation and detection scheme. The laser driver 2703that supplies a current (and a voltage) to a laser source 2704 oroptionally to a laser and an external optical modulator to activate thelaser output 2704 and encode a signal on the output radiation from thelaser output. The modulation scheme to encode the data can be comprisedof pulses of various lengths and duty cycles and by other schemesdescribed throughout the specification. The pulsed or modulated laserbeam is then optionally fed through one or more optics (beam shaper2705) to condition the beam, such as providing a beam collimation. Thelaser beams is then distributed or directed amongst a large area eitherto scan and illuminate sequential spatial coordinates as individualpixels or to illuminate large areas representing several pixelssimultaneously that partially or fully comprising the image. In theformer “one pixel at a time” configuration the laser can be scanned withmacro mechanical systems 2706 such as rotating scanners or goniometers,or the scanning could be through a micro-scanner such as a MEMS scanningmirror or a microdisplay such as a DLP chip or LCOS chip, or other. Inthe latter configuration, the laser beam can be distributed to a largerarea either through a beam expanding optics, or could be expanded with ascanning function using a micro-scanner such as a MEMS scanning mirroror a microdisplay such as a DLP chip or LCOS chip, or other. After beingspatially distributed with the scanner or microdisplay the laser beamcan optionally be fed through one or more optics (beam shaper 2707) forfurther beam conditioning before entering the outside world through anoutput transmitter 2708 at exit path. Once in the outside world thescanned laser beam illuminates a target area and the reflected orbounced light is received in an input receiver 2719 where the light canoptionally be coupled through optics (beam shaper 2717) prior tostriking some sensors which could be a photodiode or array ofphotodiodes 2715. The electrical signal generated by the photodiode ordetector array 2715 is then optionally amplified in an electricalamplifier 2713 such as a transimpedance amplifier. This electrical datais then transported to the control and processing unit 2702 where thedetected signal is processed to generate a map of the environment. Theprocessing can be comprised of a time of flight calculation or acoherent heterodyne detection. Based on the data received, theprocessing unit 2702 may modify the signal characteristics to the laserdriver 2703 to optimize the LIDAR performance or alternate operationalmodes. FIG. 21 is of course a simplified schematic diagram and othercomponents and schemes could be included in the LIDAR system. Forexample, a GPS or IMU may be included.

According to various embodiments of the present invention combiningLIDAR and gallium and nitrogen containing laser diodes, the optimumchoice of laser wavelength within the LIDAR system is dependent on theapplication considering sensitivity, efficiency, size, and safetyrequirements. LIDAR systems with wavelengths in the 600 to 1000 nm, forexample 905 nm, are most common for non-scientific applications. Theyare inexpensive, but since they can be focused and easily absorbed bythe eye, the maximum power is limited by the need to make them eye-safe,which is a requirement for most applications. A common wavelengthalternative, 1550 nm lasers, are eye-safe at much higher power levelssince this wavelength is not focused by the eye, but the detectortechnology is less advanced and so these wavelengths are generally usedat longer ranges and lower accuracies. They are also used for militaryapplications as 1550 nm is not visible in night vision goggles, unlikethe shorter 1000 nm infrared laser.

In some embodiments of this invention including for airborne topographicmapping applications, the LIDAR system may include a 1064 nm diode laserdiode as opposed to the conventional 1064 nm diode pumped YAG laserscommonly used. In other embodiments where shorter wavelengths such asvisible wavelength are preferred including underwater LIDARapplications, the laser wavelength may be configured with a diode laserranging from about 420 nm to about 532 nm wherein the shorterwavelengths penetrate water with much less attenuation than does 1064nm. The use of direct diode gallium and nitrogen containing laser diodesaccording to this invention versus conventional systems using 532 nmfrequency doubled diode pumped YAG lasers offers reduced cost, size, andweight, while offering the possibility of higher efficiency.

Key laser operating parameters that determine LIDAR system performanceinclude the laser repetition rate or pulse, which controls the datacollection speed and the sensitivity. Pulse length is generally anattribute of the laser cavity, structure, and parasitics, the number ofpasses required through the gain material. Better target resolution isachieved with shorter pulses, provided the LIDAR receiver detectors andelectronics have sufficient bandwidth. Since gallium and nitrogencontaining laser diodes can be designed to offer very high modulationbandwidths of 3 to GHz and greater, ultra-short pulses offering improvedresolution compared to prior art are possible according to thisinvention. The embodiments included in this invention offer advantagesover prior art that rely on frequency doubled green lasers and YAGlasers, which are not as efficient, low cost, compact, and/or capable ofthe short pulse lengths of the diode lasers according to this invention.

In some embodiments of the present invention conventional LIDARtechnology and laser sources are combined with gallium and nitrogencontaining laser diodes and laser based light sources, including smartlighting source. That is, the LIDAR system could utilize moreconventional wavelengths and laser sources such as 905 nm, 1000 nm, 1064nm, or 1550 nm lasers and the violet or blue laser diode contained inthe laser based lighting system would be used solely for the laser basedvisible illumination source, which could be a smart laser light sourceincluding sensors, feedback loops, and or dynamic color or spatialpatterning according to this invention. In these embodiments, the novelcombination of the laser based light source and the LIDAR technologyenable new and improved system performance such as enhancedcapabilities, smaller and/or more compact lighting and LIDAR systems,lower cost systems, and more rugged or robust systems. In one example,the combined LIDAR and laser based lighting system would enable asmaller size, a lower cost, and/or an easier system for the user, or amore reliable combined system than the equivalent but separated LIDARand laser based lighting systems would offer. In another example, thefunctionality or sensitivity of the combined LIDAR system and laserbased lighting system would be configured for an improved performancecompared to the LIDAR system and laser based lighting system as separatesystems. These embodiments could find application in autonomous objectsor vehicles, internet of things applications, or other consumer,defense, auto, or specialty application.

In preferred embodiments of the present invention, gallium and nitrogencontaining laser diodes within a laser based lighting systems form aLIDAR sensing wavelength. That is, the same violet or blue emittinglaser diodes exciting wavelength converter material to generate alighting function are also spatially scanned and illuminate the targetto form a LIDAR surveying function. In some preferred embodiments onlythe gallium and nitrogen containing laser diode emitted wavelength isused for the LIDAR scanning, wherein in one example the direct coherentlaser beam could be scanned on the target and in another example areflected or scattered laser beam may be re-collimated and used for theLIDAR scanning. In yet another embodiment the optical emission from thewavelength converter material such as a yellow or a green red emissionis also used for LIDAR scanning either separately or in addition to theemission from the gallium and nitrogen containing laser diode such as aviolet or a blue emission. By including multiple wavelengths in thescanning system enhanced detection can be enabled.

The laser scanning and optical design play a critical role in the LIDARsystem's sensitivity, resolution, and refresh rate. Included in thisinvention for LIDAR systems with gallium and nitrogen containing laserdiodes are several options to scan the azimuth and elevation, includingdual oscillating plane mirrors, a combination with a polygon mirror, adual axis scanner, MEMS mirrors, DLP chips, fiber scanners, LCOS, etc.Any and all of the beam steering elements described throughout thisinvention are candidate options for scanning systems in LIDAR. Opticchoices affect the angular resolution and range that can be detected.Optical components used for the transmission and collection signaloptical paths may include apertures, hole mirrors, beam splitters,reflectors, fast axis collimating lenses, slow axis collimating lens,reimaging optics, magnifying optics, dichroic mirrors, diffusers, etc.

In some embodiments, in addition to the laser illumination source, thelaser beam scanning or expanding apparatus such as a MEMS micro-scanningmirror or beam expanding optics, and the optical architectures used fortransmission and collection, a suitable light detection system isrequired. The complexity and architecture of this system will beinfluenced by the type of LIDAR system [coherent versus incoherent], thewavelength range of the system, along with the sensitivity and speedrequirements of the detection. According to this invention, the primaryphotodiode technologies utilized in LIDAR include solid statephotodetectors, such as silicon avalanche photodiodes, siliconphotodiodes, GaAs photodiodes, GaN photodiodes, photomultipliers, orothers. The detection system can be configured to detect the return orreflected signal one pixel at a time such as with a single detectorconfiguration or can be configured to detect the return or reflectedsignal from large quantities of pixels simultaneously to capture partialor complete frames at a time.

For low-light detection in the receiver, a designer has three basicdetector choices: the silicon PIN detector, the silicon avalanchephotodiode (APD), and the photomultiplier tube (PMT). APDs are widelyused in instrumentation and aerospace applications, offering acombination of high speed and high sensitivity unmatched by otherdetectors. The APD in the receiver converts the received light pulse toan electrical signal. It outputs a current proportional to the incidentlight. A transimpedance amplifier is then used to convert the current toa voltage signal. A good transimpedance amplifier should have high gain,high input impedance, ultra-low voltage and current noise, and low inputcapacitance. It normally has a FET or MOS input stage to meet theserequirements. Input noise voltages <1.0 nv√Hz and current noise <15fA√Hz are achievable with high performance devices. The output of thetransimpedance amplifier is generally converted to a differential signaland amplified before digitization by an ADC. The transmitted pulse isgenerally greatly attenuated (atmospheric conditions etc.) leading to alarge difference in strength between transmitted and received pulses.Objects in the near vicinity of the transmitter can also reflect highpower signals back to the receiver. This leads to demanding dynamicrange requirements for the receive system. The receive system should besensitive enough to deal with full power and very low reflected pulses.Dynamic range requirements in the order of 100 dB are not uncommon. Thisdynamic range is generally achieved by using a Variable Gain Amplifier(VGA) or Digital VGA (DVGA) in the front end prior to the ADC. (LIDARSystem Design for Automotive/Industrial/Military Applications, TexasInstruments)

In several applications, LIDAR sensors are mounted on mobile platformssuch as airplanes or satellites and require instrumentation to determinethe absolute position and orientation of the sensor. Such devicesgenerally include a Global Positioning System (GPS) receiver and anInertial Measurement Unit (IMU) such as au accelerometer.

LIDAR imaging can be achieved using both scanning and non-scanningsystems. For example, “3D gated viewing laser radar” is a non-scanninglaser ranging system that applies a pulsed laser and a fast gatedcamera. Additionally, laser beams can be expanded to capture large areaswithout having to actively scan the beam across the area. There areseveral approaches for non-mechanical beam steering or scanning of thelaser signal. In one example, multiple single frequency lasers are usedfor coherent beam steering. The general principle is to deploy an arrayof transmitters for which the phase of each of the waves produced by thelaser can be controlled. The combined wavefront from the transmitterarray is then manipulated to travel in a particular direction throughdynamic control of the individual phases. In another embodiment, theoutput from a single highly coherent emitter is split into multiplepaths wherein the phase of the emitted light in each path can beindividually manipulated to control the wavefront comprised when thebeams are recombined. Alternatively, a wavelength tunable laser outputcan be directed through a grating wherein the direction of the outputemission from the grating is wavelength dependent. By dynamically tuningthe wavelength of the laser the output beam direction can be controlled.Research has begun for virtual beam steering using DLP technology. Allof these beam steering and scanning technologies are applicable to thepresent invention including a gallium and nitrogen containing laserdiode.

In some preferred embodiments of the present invention, imaging LIDARsystems illuminate the entire field with a pulse of light, and use ameasurement such as a time of flight measurement to gather the depthcoordinate of tens to millions of spatial points in parallel, one frameat a time. These receiver systems must utilize arrays for paralleldetection of the return signal from the many spatial points. In oneembodiment high speed detectors and modulation sensitive detector arraysare included in the LIDAR systems. These arrays are can be built onsingle chips using CMOS and hybrid CMOS/CCD for low cost, reliable, andhigh performance parallel detection. In this configuration each pixelcan perform some local processing such as demodulation or gating at highspeed, down-converting the signals to video rate so that the array maybe read like a camera. Using this technique many dense pixel arrays orchannels can be acquired simultaneously. In some embodiments of thepresent invention, homodyne detection with an electronic CCD or CMOSshutter is employed for high resolution 3D LIDAR.

In another embodiment of a parallel detection LIDAR system, an opticalarray (e.g. microdisplay) such as a DLP chip or LCOS chip can be used tocollect the simultaneous return signals from the various spatial points.The optical array would then direct the reflected light from the variousspatial points to a detector wherein the detector could be a detectorarray or a single detector. Through proper data processing, algorithmdesign, and synchronization the depth coordinate from the variousspatial points would be computed.

In some embodiments a MEMS scanner mirror is included in the detectionscheme in the receiver unit. For example, the MEMS scanner would becombined with the optical array to individually pick off the signal fromeach pixel and direct it to a single photodiode. In another moredesirable example, a MEMS scanning mirror would be configured to rasterover the LIDAR illuminated area and capture the return signals from thevarious spatial coordinates wherein the various rotational positions ofthe MEMS mirror would correlate to the various pixels in an image orframe. The MEMS mirror would then reflect the return signal to adetector such as a photodetector, CMOS detector, or detector array. Inyet another preferred and simplified embodiment, a single or multipleMEMS or micro-display is used both on the transmitter side of the LIDARsystem to raster or distribute the illumination pulses over the targetarea and to collect the reflected signal in the receiver side of theLIDAR system.

In one specific embodiment a microdisplay is used to either raster thelaser imaging signal such as a pulse with a beam steering member such asa MEMS scanning mirror or with a 2D array microdisplay such as a DLPchip or LCOS chip to illuminate the target area. In one configurationthe detection system is configured with a CMOS detector array. Inanother configuration the detection system uses the microdisplay coupledback to a photodiode.

In another advanced scheme a coherent imaging LIDAR is included. Thecoherent imaging LIDAR includes a synthetic array heterodyne detectionto enable a staring single element receiver to act as though it were animaging array.

In some embodiments of the present invention a laser based light sourceis included with a LIDAR system on a device or mobile machine such as avehicle, automobile, aircraft, marine vessel, underwater vessel, drone,satellite, helicopter, weather balloon, or other apparatus. In theseembodiments the LIDAR source could be a conventional LIDAR system thatis not necessarily housed or contained in same packaging as the laserbased light source, but must at least be contained within or onboard thesame apparatus to provide a combined functionality of laser basedlighting and LIDAR imaging. For example, the LIDAR imaging system wouldprovide a 3-dimensional mapping of the environment and the laser basedlighting system would provide a specialized lighting function such as along range light for increased visibility or safety, spotlighting, or asmart lighting function, which could be comprised of any of the smartlighting functions described in this invention such as spatially dynamiclighting, visible light communication [VLC] such as LiFi, dynamic colorcontrol, which could be combined with sensors for closed feedback loops.The unique properties of laser based illumination systems such as thehigh directionality or high resolution dynamic display and patterncapability combined with real time LIDAR imaging can improve safety andfunctionality of SMART systems used in many applications includingautonomous applications.

FIG. 22A shows a schematic diagram of an apparatus or mobile machinecomprising both a LIDAR system and laser based visible light sourceaccording to some embodiments of this invention. The apparatus 2800 suchas a mobile machine is comprised of at least one power source 2801 thatserves as the energy source for both the laser light illumination system2810 and the LIDAR system 2820. The laser light illumination system 2810is comprised of a gallium and nitrogen containing laser diode 2811operating with a first electromagnetic radiation output in the bluewavelength region (420 to 485 nm) or the violet wavelength region (390to 420 nm). The first output electromagnetic radiation is an incidentbeam onto a wavelength conversion member such as a phosphor materialwhere at least a fraction of the first blue or violet peak wavelength isconverted to a second peak wavelength to generate a white light as anoutput beam with a mixed first peak wavelength and the second peakwavelength. In some preferred embodiments the wavelength conversionmember or phosphor material is operated in a reflection mode to producethe output beam relative to the incident beam. In other preferredembodiments the wavelength conversion member or phosphor material isoperated in a transmission mode to produce the output beam relative tothe incident beam. Once the white light is generated it is coupledthrough an optical member such as a collimating optic to shape theoutput beam.

The LIDAR system 2820 is comprised of a laser subsystem having at leasta transmitter module 2822 containing a laser, wherein the transmitter2822 is configured to generate and direct laser light pulses as one ormore sensing light signals to the surrounding environment. The LIDARsystem 2820 also includes a detection subsystem including at least areceiver module 2823, which functions to detect light signals uponreturns of the one or more sensing light signals after reflection offthe surrounding environment. Further the LIDAR system 2820 includes aprocesser 2821 to synchronize the transmitter 2822 and receiver 2823,process both the transmitted laser light pulses and reflected lightsignals, and perform time-of-flight calculations to determine thedistances to all surrounding objects and generate a 3-dimensional mapthereof.

The laser light illumination system 2810 can optionally be coupled tothe LIDAR system 2820 through a signal processor and/or generator 2802that is configured to control the laser light illumination system basedon feedback or information provided from the LIDAR system 2820. In oneexample the LIDAR system 2820 detects an oncoming mobile object. Toprevent glare to the oncoming object the processing unit 2802 adjuststhe current to the laser light illumination system 2810 to dim or reducethe brightness of the laser light illumination system 2810 to preventglare hazards. In an alternative example, the LIDAR system 2820 detectsa moving object that the operator of the mobile machine may not be awareof and could prevent a safety hazard such as a collision hazard. In thiscase the processing unit 2802 generates a signal to the laser lightillumination system 2810 to modify the light characteristic such asactivating a spotlight function on the moving object to bring it to theoperator's attention. Additionally, the laser light illumination system2810 could be a dynamic source with the ability to dynamically changethe beam angle and/or the spatial pattern/location of the light outputsuch that the moving object can be dynamically tracked with a spotlight.

In one example of the present embodiment, components of the laser basedlighting system 2810 and the LIDAR system 2820 could be housed within acommon package as an integrated system 2800 or as separate systems. Forexample, the LIDAR system 2820 and laser based lighting system 2810could be housed within the headlamp of an automobile such as anautonomous vehicle. In another example the laser based lighting systemand LIDAR system could be contained in the lighting housing on a drone.

In one example, a laser based lighting system and a LIDAR system areprovided on a mobile machine such as an autonomous vehicle or dronewherein the LIDAR system is used for scanning and navigation and thelaser based lighting system is used for spotlighting objects or terrainto provide a communication or warning. In one preferred embodiment, theLIDAR function and illumination function are connected via a loopwherein the LIDAR image is acting as a sensor signal to feedback intodynamic laser based illumination pattern. For example, if the LIDARmapping detected an animal on the side of the road, the laserillumination source could be configured to preferentially spotlight it.In another example, if an oncoming car is detected by the LIDAR mappingthe laser based illumination pattern can be configured to blank out ordarken the beam on the oncoming traffic. Of course, there are manyexamples of how a dynamic illumination pattern and a dynamic LIDARscanning pattern can be used in conjunction for added functionality andsafety in many applications including automotive, recreation,commercial, space and defense, etc.

FIG. 22B shows an example using the apparatus integrating both a LIDARsystem and laser based visible light source of FIG. 22A according tosome embodiments of the present invention. Referring to FIG. 22B, anautomobile comprised both a LIDAR system and a laser based light source.In this embodiment the LIDAR system is used to spatially map theenvironment and the laser based light system is used to illuminate thespecific objects and the general surroundings with visible white light.

In one embodiment, the laser based lighting system could be used forcommunication via. VLC or LiFi to transmit a data signal to be detectedby a surrounding machine, device, or human. For example, the transmittedsignal could be used to transmit data about the speed, velocity,trajectory, or intention of the subject apparatus that houses the LIDARsystem. In another embodiment a dynamic spatial illumination is used tocommunicate with surrounding objects, devices, or humans by projectingshapes or signs onto visible surface. In yet another embodiment, alighting system with dynamic color tuning is used to communicate tosurrounding objects, devices, or humans where the color or brightness ofthe laser based light would be changed to communicate a message. Suchnovel combinations of LIDAR and laser based lighting systems couldenable capabilities for autonomous or semi-autonomous vehicles, devices,drones, boats, vehicles, and other machines with the critical ability toimage the environment for navigation while simultaneously illuminatingand communicating with objects, devices, and humans/animals within theenvironment.

In one example, the LIDAR system operates with an infrared wavelengthsuch as a wavelength between 800 nm and 1100 nm (e.g., typically at 905nm or 1064 nm), 1100 nm to 1450 nm, or 1450 nm to 1800 nm and the laserbased light system operates with a laser excitation source wavelength ofbetween 400 and 480 nm and wavelength conversion member such as aphosphor. The laser light source would be configured for a reflectionmode or transmission mode coupling of the excitation laser light to thephosphor member. The laser based light source would be configured toreact to certain or predetermined environmental conditions detected bythe LIDAR system. The laser based light system and LIDAR systemcomponents could share a common package member or base member, but alsocould be completely separate and mounted on different locations of thevehicle or apparatus.

In some embodiments of the present invention, a laser based light sourceis fully or partially integrated with a LIDAR system and configured onan apparatus device such as a mobile machine like a vehicle, automobile,drone, aircraft, marine vessel, underwater vessel, or other apparatus.In these embodiments the LIDAR system would be at least partiallycomprised of one or more components shared with the laser based lightsource, such as the excitation laser diode in the laser based lightsource. Such a system wherein at least a portion of the LIDAR functionis integrated into the laser based light system would offer potentialbenefits of overall reduced size, cost, and weight of the systems, alongwith opportunity for increased functionality, sensitivity, or enhancedcapability. In one example according to this embodiment the laser basedlight system and at least a portion of the LIDAR are housed or containedin the same packaging.

In one example of this embodiment, the emission from a violet or bluelaser diode source with a wavelength from 390 nm to 480 nm used toexcite a wavelength converter member such as a phosphor member togenerate the lases based white light is also for the laser scanningfunction in the LIDAR system. The blue or violet laser diode emissionmay be split into two beams wherein a first beam is primarily used toexcite the phosphor and generate a light such as a white light and thesecond beam is collimated to spatially map a surrounding environment. Inone embodiment the collimated laser light for LIDAR sensing uses ascanning member to spatially scan the laser beam over a predeterminedsubject area based on the rastering pattern of the scanning mirror. Thescanning member could be a dual or single axis scanning MEMS device thatspatially sweeps the violet or blue wavelength collimated laser beamacross the environment and senses the returned (scattered/reflected)laser beam to calculate the distance using a time of flight method, andhence generating a 3-dimensional map. In an alternative embodiment anoptical beam shaping element is used to expand the blue or violet laserbeam to a predetermined divergence to simultaneously illuminate a totalsubject area. In a common configuration the laser source and/or scanningmember would be configured to generate a periodic short pulse of lightor a modulated intensity scheme to enable synchronization of thetransmitted and detected signal wherein a time-of-flight calculation orcoherent detection calculation can be used to compute distances and mapthe subject area. In this embodiment of the present invention the lasersource is being used both for the lighting function and the LIDARfunction. One challenge with using the visible wavelength for LIDARsensing is the eye safety concern. However, this can be overcome byusing short pulses of light to limit eye exposure, by limiting theoutput power to an eye safe level, and/or by using a scanningmethodology and safety algorithm to prevent damage or prolonged eyeexposure.

FIG. 23 is a simplified schematic diagram of a laser light illuminationsystem integrated with a LIDAR system according to some embodiments ofthe present invention. As shown in the figure, the integrated system2900 is configured with a power source 2901 to supply power to both theLIDAR system and the laser light illumination system. Optionally,separate or multiple power supplies 2901 could be used along with acontroller 2902 including a processor and some drive electronicsconfigured to receive power from the power supply 2901 and receive dataor signals from receiver components 2931 of the LIDAR system. Based onexternal inputs 2990 such as user inputs or predetermined inputs toprovide specified functionality and power supplied from the power supply2901, the controller 2902 determines appropriate drive signals beingsent to one or more gallium and nitrogen containing laser diodes 2903.The drive signal is configured to drive the current and voltagecharacteristic of the laser diode 2903 to generate an appropriateintensity pattern from the laser diode to provide a firstelectromagnetic radiation characterized with a first peak wavelengthsuch as a blue or violet peak wavelength. In one embodiment the drivesignal is configured to generate both the appropriate pattern of laserlight required in the laser illumination source with the desiredbrightness and luminous flux along with the laser emission for the LIDARscanning function with the desired sensing light signal or laser pulsefor the LIDAR system to sense reflected light signal based on thesensing light signal and perform time-of-flight calculation based onboth the sensing light signal and the reflected light signal. In analternative embodiment an optical modulator could be included toseparately encode a signal on the light for the LIDAR system or for thelaser light illumination source.

As shown in the FIG. 23, the first electromagnetic radiation at thefirst peak wavelength from the laser diode 2903 is then split into twoseparate optical paths. The first optical path is incident on awavelength conversion member 2911 (e.g., a phosphor) where at least afraction of the first electromagnetic radiation with the first peakwavelength is converted to a second electromagnetic radiation (emissionfrom the excited phosphor) with a second peak wavelength. Optionally,the second peak wave length is in yellow color range. In a preferredembodiment, the second electromagnetic radiation is mixed with a partialportion of the first electromagnetic radiation to produce an outputelectromagnetic radiation of the laser based illumination system as awhite light. The resulting output electromagnetic radiation is thenconditioned with one or more beam shaping elements 2912 to provide apredetermined collimation, divergence, and pattern. Optionally, a beamsteering element can be added to the laser based illumination system tocreate a spatially dynamic illumination. In some embodiments anadditional beam shaping element such as a collimating optic is used tocollimate the laser light prior to incidence on the wavelengthconversion member 2911. Additionally, optical fibers such as glass orpolymer fibers or other waveguide elements can be used to transport thelaser light from the laser diode 2903 to the wavelength conversionmember 2911 to create a remotely pumper conversion.

According to FIG. 23, the second optical path directs theelectromagnetic radiation with the first peak wavelength to the LIDARtransmitter module 2921 where it can be combined with other transmittercomponents. In some embodiments a collimating optic such as a lens isused to collimate the laser light prior to entry in the transmittermodule 2921 of the LIDAR system. Additionally, optical fibers such asglass or polymer fibers or other waveguide elements can be used totransport the laser light from the laser diode 2903 to the LIDARtransmitter module 2921. As described previously, an optical modulatorcould be included within this second optical path to generate an opticalpulse or other optical signal as a sensing light signal required for thedesired LIDAR function. Before exiting to the outside environment, thesensing light signal of the LIDAR system can be properly conditioned bytransmission optics 2922 for LIDAR system with the appropriatedivergence and direction to scan the sensing light signal over thedesired target area of the surrounding environment. A map of the desiredtarget area can be captured by the LIDAR system in various waysincluding scanning the sensing light signal using a dynamic scanner suchas a MEMS scanning mirror, recording image using a microdisplay such asa DLP, or LCOS, and/or simply expanding or shaping the beam using basicoptics 2932 such as lens, mirrors, and diffusing elements. Once all ofthe signal processing and beam conditioning are completed by thetransmission optics 2922, the LIDAR sensing light beam is projectedexternally to the target area where it reflects and scatters off of thevarious remote target objects in the surrounding environment andfractionally returns to the receiver module 2931 of the LIDAR system.The receiver module 2931 is comprised of some receiver opticalcomponents and a signal processor (such as analog-to-digital converter),a detection member 2932 such as a photodiode, a photodiode array, a CCDarray, an antenna array, a scanning mirror or microdisplay coupled to aphotodiode or other configured to detect reflected or scattered lightsignals from the remote target object and convert them to electricalsignals. The electrical signals detected by the detection member 2932are received by the receiver module 2931 and then used to calculate atime of flight for the transmitted and detected LIDAR signal such as asensing light beam. Optionally, a spatial map of the remote targetobject can be generated by the signal processor associated with thereceiver module 2931. The calculations or processing to determine thetime of flight and the spatial map can be done directly in the receiver2931. Alternatively, the spatial map generation is done in the separateprocessor unit 2902.

Of course there are many novel configurations of this embodiment can berealized. For example, the light source of the laser based illuminationsystem could be comprised of multiple gallium and nitrogen containinglaser diodes wherein one or more of the multiple laser diodes are usedfor the LIDAR scanning function. In an example, the multiple gallium andnitrogen containing laser diodes operating in a range of 390 nm to 550nm are used in the LIDAR system for multi-wavelength (multi-spectral) orhyper-spectral LIDAR illumination scanning. Such wavelength diversitycoupled with corresponding signal conditioning and detection can allowincreased sensitivity and/or provide the LIDAR user with moreinformation regarding the environmental landscape. In alternativeembodiments other wavelength ranges could be generated from the galliumand nitrogen containing laser diodes such as ultra-violet, cyan, green,yellow, orange, or red. Additionally, any number of scanning, rastering,or imagine generating technologies can be included such as DLP, LCOS,and scanning fiber.

In an alternative embodiment, a laser based lighting system wherein thegallium and nitrogen containing laser diode wavelength is used for LIDARillumination is configured within a conventional LIDAR system making useof standard LIDAR wavelengths such as 905 nm, 1000 nm, 1064 nm, 1550 nm,or other. By combining the wavelengths such as a blue wavelength from arange of 390 nm to 480 nm from the gallium and nitrogen containing laserdiode with an infrared wavelength from a conventional LIDAR system canhave an increased sensitivity or functionality. This increasedsensitivity and functionality is achieved by using the separatewavelengths to sense different characteristics of the environment basedor based on differential analysis in the return signals or echoes suchas the amplitude, time of flight, or phase. In some embodiments, nogallium and nitrogen containing laser diodes emitting at longerwavelength are used in the system including GaAs or InP based laserdiodes.

In another embodiment, the laser light excitation beam that has beenreflected and/or scattered from the wavelength conversion member in thelaser light illumination system can be used for realizing the LIDARsensing function. In the embodiment, a beam splitter or similarcomponent is eliminated to “pick off” a part of the direct laser beamfor LIDAR sensing prior to exciting the wavelength converter member. Forexample, a violet to blue laser with a first wavelength in the range of390 nm to 480 nm from a GaN-based laser diode excites a wavelengthconversion member such as a phosphor to generate a longer secondwavelength emission. In one example the second wavelength is ayellow-color emission that mixes with the remaining violet or blue-coloremission from the GaN-based laser diode to make a white light emission.This white light emission, which could have a Lambertian pattern, isthen collimated and coupled to a 1 or 2-dimensional scanner such as ascanning MEMS mirror. The scanning member of the scanner would thensweep the collimated beam of light amongst the environment andsurroundings and serve as a LIDAR scanning illumination member. Theviolet or blue first wavelength within the collimated white light beamsweeps across the environment and senses the returned(scatter/reflected) laser beam to calculate the distances from thescattering objects using a time of flight method, and hence generating a3-dimensional map. The violet or blue laser provided for LIDAR sensingis characterized by by high power levels in one range selected from 1 mW10 mW, 10 mW to 100 mW, 100 mW to 1 W, and 1 W to 10 W capable ofsensing and mapping the remote target object under damp condition withrelative humidity level in each of following ranges of greater than 25%,greater than 50%, greater than 75%, and greater than 100%.

In a common configuration of this embodiment the laser source and/orscanning member would be operated to generate a periodic short pulse oflight or a modulated intensity scheme to enable synchronization of thetransmitted and detected signal. The detector could be configured with anotch-pass filter designed to accept wavelengths only within a narrowband (i.e., 2-20 nm or 20-100 nm) centered around the laser emissionwavelength such as the violet or blue wavelength in the excitationsource. Such a configuration would lend itself optimally to a spatiallydynamic laser-based light embodiments described throughout thisinvention that combines a microdisplay such as a MEMS scanning mirrorwith the laser based lighting/illumination technology. Further, smartlaser-based lighting systems would offer sensor feedback for closedfeedback loops enabling the LIDAR sensing and smart laser lightingfunctions to activate and respond to changes in environmentalconditions.

FIG. 24 is a simplified schematic diagram of a laser light illuminationsystem integrated with a LIDAR system according to some alternativeembodiments of the present invention. As shown in the figure, theintegrated system 3000 is configured with a power source 3001 to supplypower to both the LIDAR system and the illumination system (note that insome embodiments separate or multiple power sources could be used) alongwith a processor and control unit 3002 configured to receive power fromthe power supply 3001 and data or signals from the receiver portion 3031of the LIDAR system. Based on external inputs 3090 such as user inputsor predetermined inputs to provide specified functionality and powersupplied from the power supply 3001, the processor and control unit 3002determines the appropriate driving signal based on the external inputs3090 to drive one or more gallium and nitrogen containing laser diodes3003. The driving signal is configured to determine a current andvoltage characteristic of the laser diodes 3003 to generate theappropriate intensity pattern provided as electromagnetic radiation witha first peak wavelength such as a blue or violet peak wavelength. In oneembodiment the driving signal is configured to generate both theappropriate pattern of laser light required in the laser illuminationsource with the desired brightness and luminous flux along with thelaser emission for the LIDAR scanning function with the desired signalor laser pulse for LIDAR sensing and time of flight calculation. In analternative embodiment an optical modulator could be included toseparately encode a signal on the light for the LIDAR system or for thelaser light illumination source.

As shown in the FIG. 24, the primary electromagnetic radiation at thefirst peak wavelength from the laser diodes 3003 is directed as anincident light into a wavelength conversion member 3004. The wavelengthconversion member 3004 is a phosphor material which is excited to reemitlight with a longer wavelength by the incident light of a certainwavelength. Thus, at least a fraction of the primary electromagneticradiation with the first peak wavelength is converted to a secondaryelectromagnetic emission with a second peak wavelength, such as a yellowpeak wavelength. In a preferred embodiment, the secondaryelectromagnetic emission with a second peak wavelength is combined ormixed by one or more beam shaping elements 3005 with at least a fractionof the electromagnetic radiation with the first peak wavelength toproduce a white light. Optionally, the white light as the combinedemission includes at least a first peak wavelength in violet or bluerange and a second peak wavelength in yellow range. Additionally, theone or more beam shaping elements 3005 is configured to provide apredetermined collimation, divergence, and pattern for guiding thecombined emission for both illumination and LIDAR sensing.

As seen in the FIG. 24, at least a portion of the combined emission isoutputted and shaped as a LIDAR scanning emission. In an embodiment, thea LIDAR scanning emission generated by the one or more beam shapingelements 3005 includes a first sensing light signal with the first peakwavelength and a second sensing light signal with the second peakwavelength based on the received laser-based white light. On the onehand, the LIDAR scanning emission could be fed through a LIDARtransmission components 3021 for signal shaping, filtering,wavelength-dependent transmitting, beam steering (which could be activebeam steering with a MEMS or other), etc. before a beam of the firstsensing light signal and the second sensing light signal is projectedvia a LIDAR signal transmission module 3022 into the environment forscanning over a remote area including the target objects and theirsurroundings. On the other hand, a remaining portion of the combinedemission is provided as a beam for illumination. The beam could befurther processed by additional beam shaping optical components 3011 tocollimate to 15 degrees or less as a better illumination source fortarget objects with enhanced directionality and reduced attenuation.Optionally, a beam steering element 3012 is additionally included tomanipulate the beam of the illumination source to create a spatiallydynamic illumination of at least part of the target objects.

In some embodiments, an additional beam shaping element such as acollimator is used to collimate the laser light prior to incidence onthe wavelength conversion member 3004. Additionally, optical fibers suchas glass or polymer fibers or other waveguide elements can be used totransport the laser light from the laser diodes 3003 to the wavelengthconversion member 3004 to create a remotely pumper conversion.

In an alternative embodiment, the white light outputted from the one ormore beam shaping elements 3005 as a combined emission of a primaryemission from the laser diode and a secondary emission from thewavelength conversion member 3004 are split into two optical pathwaysfor separate conditioning and steering possibilities respectively with afirst beam for the illumination system and a second beam for the LIDARsystem. In other embodiments, the LIDAR system and the laserillumination system may follow the same optical pathway such that theillumination area and the 3D scanned area from the LIDAR system arenearly the same.

In another alternative embodiment, the white light outputted from theone or more beam shaping elements 3005 is fed through a single opticalpathway to a beam projector that includes the LIDAR transmissioncomponents 3021, the LIDAR signal transmission module 3022, the beamshaping optical components 3011, and the beam steering element 3012 foraccomplish multiple tasks of signal processing, filtering, beam shaping,collimating, and projecting to generate the first sensing light signalwith the first peak wavelength, the second sensing light signal with thesecond peak wavelength, and the beam of white light for illumination.Alternatively, the beam projector contains a hybrid collimator to handlethe combined emission. The hybrid collimator includes a centercollimator configured to collimate a portion of the white light as aLIDAR sensing beam and an outer collimator configured to collimate aremaining portion of the white light as an illumination beam. Inparticular, the portion of the white light collimated as a LIDAR sensingbeam includes a first sensing light signal with the first peakwavelength from primary laser diode 3003 and a second sensing lightsignal with the second peak wavelength from the secondary emission ofthe wavelength conversion member 3004. The center collimator isconfigured to collimate beams of the first sensing light signal and thesecond sensing light signal to less than 1 or 2 degrees which ispreferred for LIDAR sensing light scanning and return light detectionwith a highly directional beam over one or more target objects andsurrounding environment. The outer collimator is configured to collimatea beam of the white light to less than 15 degrees for simplyilluminating the one or more target objects.

As described previously, the laser light illumination system integratedwith a LIDAR system includes an optical modulator configured to generatea pulse signal required for the desired LIDAR sensing function. Thetarget LIDAR mapping area can be captured in various ways by scanningthe LIDAR sensing light signals via optics for LIDAR signal transmissionincluding a dynamic seamier such as a MEMS scanning mirror, amicrodisplay such as a DLP, or by simply expanding or shaping the highlycollimated beam using basic optics such as lens, mirrors, and diffusingelements. The optical modulator is configured to provide a modulationsignal with a first rate to drive the gallium and nitrogen containinglaser diode to emit the first light with a first peak wavelength whichis interrupted with a second rate, wherein the second rate issubstantially synchronized with a delayed modulation rate of the secondlight of yellow color reemitted from the wavelength conversion member.The delayed modulation rate associated with the yellow pulse from thewavelength conversion member is correlated to the rate of excitationblue pulses from the laser diode. Under slow modulation rates the pulsesmay be more or less synchronized and this may not be an issue. But underfast modulation rate, e.g., GHZ, there will be hundreds to thousands ofblue pulses underneath one yellow pulse. The secondary yellow emissionwill look like background noise as it will essentially not turn-off.This could be overcome by including pulse interruptions in theexcitation signal. These interruptions would set the bit length for theyellow color signal.

Once all of the signal transmission and beam conditioning is completed,a collimated LIDAR sensing beam including both the first sensing lightsignal and the second sensing light signal for the LIDAR system isprojected externally to a designed projection area including varioustarget objects and the surrounding environment. Optionally, the LIDARsensing beam is provided in each scanning cycle as a series of lightpulses having at least the first peak wavelength and the second peakwavelength. The first sensing light signal and the second sensing lightsignal are respectively reflected and scattered off the various targetobjects in the projection area. At least a fraction of thereflected/scattered light signal is received by a receiver module 3031of the LIDAR system. The receiver module 3031 is coupled to some opticalreceiving components 3032 including one or more optical detectors suchas a photodiode, a photodiode array, a CCD array, an antenna array, ascanning mirror or microdisplay coupled to a photodiode or other todetect the reflected/scattered light signal and convert it to electricalsignal. The receiver module 3031 further includes at least a signalprocessor to process the electrical signal into digital format andfurther to calculate a time of flight based on both the transmittedsecond sensing light signal and the detected signal in digital format.The time of flight information can be used to generate a spatial map orimage of the target objects and their surroundings.

Optionally, the receiver module 3031 includes a first signal receiverconfigured to detect reflected signals of the first sensing light signalto generate a first image of the one or more target objects, a secondsignal receiver configured to detect reflected signals of the secondsensing light signal to generate a second image of the one or moretarget objects. Optionally, the first image generated by the firstsignal receiver is synchronized with the second image generated by thesecond signal receiver to obtain a color-differential image of the oneor more target objects. The difference in attenuation between blue colorlight and yellow color light can provide information about theenvironment including the air or other space the light signals aretraveling through or the materials the light signals are reflectingfrom. Similarly, the difference in return-time for the blue color andyellow color signal light can provide information about the material thelight is traveling through due to dispersion. Optionally, thecalculations or processing to determine the time of flight and thespatial map or image of the target object/area can be done directly inthe receiver module 3031 or alternatively in the processor and controlunit 3002.

It is to be appreciated that extremely high luminance is achieved forthe laser based light sources outputted from a wavelength conversionmember (3004 such as phosphor) to be used in the LIDAR applications.Lasers by themselves are typically used in LIDAR systems largely due tothe characteristics of high directionality, low attenuation, and extremeluminance. The emission characteristics enable the laser light to behighly collimated to maintain a controlled beam to accurately anddensely survey the environment over large distances (i.e. 10 in to10,000 in). Other illumination sources such as LEDs are simply notcapable of meet such luminance requirements to enable the collimationand directionality. However, advanced laser based lighting systems usinghigh power lasers to illuminate tiny spots on phosphors and generate 300to 3,000 lumens of light from a spot size (optical aperture) of 50 μm to1000 μm can enable extreme collimation even though the emission from thephosphor (i.e., wavelength conversion member) may be Lambertian. Thus,in such a laser based lighting system the optical beam can be collimatedto less than 1 degree, less than 2 degrees, or less than 5 degrees toenable the directionality and intensity required in LIDAR applications.In some examples of all the embodiments described herein, certain andseparate optics may be used for the LIDAR system compared to thelighting or illumination system. For example, a hybrid optical beamcollimator could be used to enable a center beam collimation that isseparated from the outer beam collimation. The center beam collimationmay be a higher collimation such as less than 1 or 2 degrees to serve asthe primary LIDAR transmission beam collimator. The outer beamcollimation may be a lower collimation such as less than 15 degrees,less than 10 degrees, or less than 5 degrees and serve as the primaryillumination beam collimator. Of course, this is just merely one exampleof how the optical system could be designed to separately optimize theLIDAR transmission beam of light from the lighting system lightingcharacteristics.

The benefits of the present example are many fold. As mentioned above,integration of LIDAR systems with laser based smart lighting systemsmaking use of micro-displays is a nice additional benefit of the smartlight configuration that already requires a laser source and a scanningsystem. In this configuration the dynamic laser based light source isbeing used both for the lighting function and the LIDAR function. Bycombining the LIDAR and laser lighting function such as smart lightinginto a common device, increased functionality, reduced cost, reducedsize, and improved reliability can be achieved. These benefits arecritically important in several advanced technology applications such asautonomous vehicles, aircraft, and marine craft, along with military,defense, automotive, commercial, and specialty application where size,weight, and styling are key design parameters, and cost is alwaysimportant.

A key differentiation and benefit to the LIDAR system described in theseembodiments that employ one or more visible gallium and nitrogencontaining laser diodes is the reduced absorption in water compared tothe more common infrared wavelengths used in LIDAR. As a result, undercertain conditions these visible wavelengths will pass though moisturesuch as fog, rain, or bodies of water more freely than the infraredwavelengths allowing increased LIDAR sensitivity in operatingenvironments containing water. Thus, even though some scatteringphenomena go as the inverse 4th power of wavelength, water absorption isdramatically lower in the visible than the IR, resulting in higherefficiency performance in conditions where they may be water present,such as fog or rain. For example, using light at 450 nm compare to 905nm, scattering increases by 16; such that 6% of the light transmits.However, the water absorption at 905 nm is more than 100× that in theblue at 450 nm, resulting in more than 5 times higher signal. In oneexample, the blue wavelength from the laser excitation source providesimproved visibility and safety for an autonomous vehicle operating inmoist or wet conditions. The improved visibility in the damp conditionscould enhance safety for the vehicle and passengers within the vehicle.

FIG. 25 shows the absorption spectrum of pure water where the absorptioncoefficient is plotted as a function of the wavelength of light (asmeasured outside of the medium). The shaded area corresponds to theregion of visible light ranging from violet at a wavelength of about 380nm to red at a wavelength of about 760 nm. To the left of the visibleregion is the ultraviolet region and to the right of the visible regionis the infrared region. It is clear from this plot that in pure waterthe visible wavelengths have a lower absorption coefficient than theinfrared region where conventional LIDAR laser sources operate. In factthe absorption is about one hundred times stronger at the red end of thevisible spectrum than at the minimum of the curve, which at a wavelengthin the blue region at about 450 nm. The reduced absorption will enablethe LIDAR system based on gallium and nitrogen containing visible laserdiodes, such as blue laser diodes, to spatially map and image theenvironment with a higher accuracy in wet environments such as on rainyor foggy days or underwater. It should be noted that the absorptionspectrum in FIG. 25 is that for pure water. In practical environmentsthere will be some impurities in the water such that the optimalwavelength for minimized absorption may vary.

This embodiment using a dynamic based laser light source as theillumination source for an integrated LIDAR function enables a vastnumber of capabilities and operational concepts wherein the illuminationpattern from the laser based light source could be separate or the sameas the pattern scanned for LIDAR imaging. In one concept the sweeppattern of the scanner member provides a static optical illuminationpattern from the laser based light source dictated by the scanningprofile of the micro-display that simply places the light in constantgeometrical pattern over a certain period of time while simultaneouslyscanning and detecting the LIDAR signal to generate a 3D map of theenvironment within the illumination pattern of the light. Here, theillumination pattern and the LIDAR imaging pattern may be identical ornearly identical. The benefits of this operation mode would be to allowthe user to visually see the 3D LIDAR image in nearly exactly the fieldthey are optically illuminating with the laser based light source. Itmust be noted that in a first concept the static illumination patternmay be changed or modified based on input from users or sensors suchthat it is in a sense dynamic, but operated typically in a staticillumination mode. The system could be designed such that both the LIDARand laser light illumination pattern is periodically modified.

FIG. 26 presents a mobile machine equipped with a laser illuminationlighting system and a LIDAR system according to an embodiment of thepresent invention. As seen in the figure, in the embodiment the LIDARscanning area and the laser light illumination area are nearly identicalsuch that the illuminated area seen by the vehicle occupant wouldclosely correspond to the LIDAR 3D mapped area.

In a second concept, the illumination pattern from the laser based lightsource is again instantaneously static such that it is operatedtypically in a given illumination pattern that can be changed based onsensor detection or user inputs. However, in this concept the LIDARsweeping is occurring over a different pattern than the illuminationpattern. In one example the LIDAR pattern is surveying over a muchbroader area to generate a 3D map of the surroundings simultaneously tothe laser based light illumination pattern being generated just over asmaller selected area. One way to achieve this differential scanningarea is by using a lower intensity light signal for the areas only beingscanned by LIDAR forming the regions outside of the desired illuminationpattern such that the amount of light in these regions is only highenough for LIDAR detection, but not high enough to cause substantialvisible illumination. Further, the LIDAR signal will in manyapplications be a periodically pulsed or modulated signal that could bereduced in average intensity such that the illumination would benegligible. An example of this concept would be using the laser basedillumination source as a directed light such as a spotlight or aheadlight for a vehicle, aircraft, or marine craft to provide a veryclear visual field of view while the LIDAR system is simultaneouslysurveying a larger field of view for navigation or data collectionpurposes. Of course there are many configurations of this concept suchas the illumination pattern covering a large area than the LIDARscanning pattern.

FIG. 27 presents a mobile machine equipped with a laser illuminationlighting system and a LIDAR system according to another embodiment ofthe present invention. As seen in the figure, in this embodiment theLIDAR scanning area and the laser light illumination area are notidentical, and in the embodiment the LIDAR scanning area is much largerthan the illuminated area such that the LIDAR 3D mapped area would beextend far beyond the illuminated area seen by the vehicle occupant.

In a third concept, the laser based illumination pattern and/or theLIDAR surveying pattern can be actively dynamic wherein the patterns canbe continuously changing or adopting to the environment based on userinputs or sensor feedback inputs or they could be static for certainperiods of time or conditions. In an example, the laser based lightillumination pattern is a dynamically adjusting headlight in anautomotive configured to provide the driver or viewer with an optimalpattern for safety or performance while ensuring that that other trafficor pedestrians on the road are not blinded or disturbed by the laserbased light (i.e. glare free). As the laser based illumination system isdynamically adjusting, the LIDAR scanning system is operating in eithera static sweeping pattern mode or a dynamically changing sweepingpattern mode. In the former, the LIDAR system could be surveyingeverything that is in front of the automobile over some field of view,for example 120 degrees, to help the car navigate and detect on-coininghazards. In one preferred embodiment, the LIDAR function andillumination function are connected via a loop wherein the LIDAR imageis acting as a sensor signal to feedback into dynamic laser basedillumination pattern. For example, if the LIDAR mapping detected ananimal on the side of the road, the laser illumination source could beconfigured to preferentially spotlight it. In another example, if anoncoming car is detected by the LIDAR mapping the laser basedillumination pattern can be configured to blank out or darken the beamon the oncoming traffic. Of course, there are many examples of how adynamic illumination pattern and a dynamic LIDAR scanning pattern can beused in conjunction for added functionality and safety in manyapplications including automotive, recreation, commercial, space anddefense, etc.

One challenge with using the visible wavelength for LIDAR sensing is theeye safety concern. However, this can be overcome in various ways suchthat it is not prohibitive. First, since many of the embodimentsdescribed in this invention utilize LIDAR scanning signals with anaverage intensity and spectral composition compatible with acceptedlighting systems, the LIDAR function should come at no extra safety riskthan just the illumination source. In most applications the laser lightwill be scattered or incoherent and be equivalent to LED light which hasbeen already commonly used in many spotlight and directional lightingapplications like automotive lighting. In short, in many embodiments,the LIDAR function is achieved with standard average illuminationintensities and wavelengths commonly used in lighting products today.Additionally, the LIDAR scanning signal will often be comprised of shortpulses of light spaced at various time intervals depending on thesampling rate. The short pulses spaced in time limit eye exposure tosafe dose levels. In scanning technologies one safety concern is anevent wherein the scanner gets stuck at one position and thencontinuously illuminates a single pixel. This could lead to dangerousexposure levels to any object or person in the path of that pixel. Toprevent this from occurring, interlocks are employed where the lasershuts off or a shutter closes if the scanning or beam steering memberbecomes stuck or frozen. And again, since this approach leverages thehighly collimated output light from the laser based light source forLIDAR and illumination, the illumination will be configured to form apredetermined lux pattern that complies with regulated lightingstandards. An example of this would be to include LIDAR withinautomotive headlights using a dynamic laser based light sources suchthat the headlights are illuminating the road for the driver andgenerating 3-dimensional map. This concept of lighting and LIDAR mappingfrom a dynamic laser based light source could be extended to a multitudeof applications including autonomous or semi-autonomous vehicles,aircraft, or marine craft, and even fully human controlled autos,aircraft, and marine craft.

In an alternative embodiment of this present invention, the laser basedlighting system wherein the gallium and nitrogen containing laser diodewavelength is used for LIDAR illumination is configured within orintegrated with a conventional LIDAR system making use of standard LIDARwavelengths such as 905 nm, 1064 nm, 1550 nm, or other. By combining thewavelengths from the gallium and nitrogen containing laser diode such asa wavelength from 390 nm to 480 nm with the conventional infraredwavelength the overall LIDAR system can have an increased sensitivity orfunctionality. This increased sensitivity and functionality is achievedby using the separate wavelengths to sense different characteristics ofthe environment based or based on differential analysis in the returnsignals or echoes such as the amplitude, time of flight, or phase. Insome embodiments, no gallium and nitrogen containing laser diodesemitting at longer wavelength are used in the system including GaAs orInP based laser diodes.

Of course many other examples of these basic embodiments exist. Forexample, alternative excitation wavelengths can be used such as in theultra-violet region, in the green region, or in the blue region. Thewavelength converted light may not be configured to form a white lightwith the laser excitation. That is, the wavelength converted light fromthe wavelength conversion member such as a phosphor may not be acombination of blue and yellow or other white combinations, but could bea green color, red color, infrared color, or a combination there of. Thephosphor member could be operated in a transmissive, reflective, orcombination mode. Alternative scanning devices such as DLP chips or LCOSchips may be used to create the dynamic lighting and LIDAR sweepingfunction.

In an alternative preferred set of embodiments, the laser lightexcitation beam from the laser light source that has been reflected,transmitted through, and/or scattered from the wavelength conversionmember and the wavelength converted light are used for the LIDAR sensingfunction. This multi-spectral or multi-wavelength LIDAR system based onlaser based lighting technology would enable an increased sensitivity,increased functionality, and/or a reduced complexity of the LIDARsystem. In this example, the violet to blue laser first wavelength inthe 390 nm to 480 nm range excites a wavelength conversion member suchas a phosphor to generate a longer second wavelength emission. In oneexample the longer second wavelength is a yellow emission that mixeswith the remaining blue emission from the laser to make a white lightemission. This white light emission, which could have a Lambertianpattern, is then collimated and coupled to a 1 or 2-dimensional seamiersuch as a scanning MEMS mirror. The scanning member would then sweep thecollimated beam of white light amongst the environment and surroundingsand serve as the LIDAR scanning illumination member. The first violet orblue wavelength from the laser diode along with a converted secondwavelength such as a yellow wavelength are contained within thecollimated white tight beam, which sweeps across the environment andsenses the returned (scattered/reflected) first wavelength and secondwavelength to calculate the distances from the scattering objects usinga time-of-flight method, and hence generating a 3-dimensional map. In acommon configuration the laser source and or scanning member would beoperated to generate a periodic short pulse of light or a modulatedintensity scheme to enable synchronization of the transmitted anddetected signal. The detector system could be configured with notch-passfilters designed to accept wavelengths only within a band (i.e. 2 to 20nm or 20 to 100 nm or greater) centered around the first emissionwavelength from the laser diode, the wavelength conversion member secondwavelength, or both the first and second wavelengths. Such aconfiguration would lend itself optimally to the spatially dynamic laserbased lighting embodiments described throughout this invention thatcombine a micro-display such as a MEMS device with the laser basedlighting/illumination technology. Further, smart laser based lightingsystems would offer sensor feedback for closed feedback loops enablingthe LIDAR and smart laser lighting functions to activate and respond tochanges in environmental conditions.

The multi-wavelength LIDAR illumination source offers additionalbenefits over conventional laser source primarily using just a firstlaser emission for the LIDAR system transmission and receiving function.In this present embodiment the laser emitted radiation with a firstwavelength (i.e. about 400 nm to about 480 nm) along with the wavelengthconverted second wavelength (i.e. about 520 nm to about 660 nm) can beincluded in the LIDAR system transmission and receiving function, whichenables the possibility for enhanced functionality and sensitivity withmulti-color transmission and detection. At least two wavelengths can beused for signal transmission and detection enabling differential sensingto capture more information about the environment. Moreover, since thesecond wavelength resulting from a wavelength conversion member such asa phosphor wavelength conversion member may have a broad spectralintensity characteristic (i.e. large spectral width of greater than 5nm, 10 nm, or 50 nm), hyperspectral LIDAR imaging could be enabled.

As an example, the multi-wavelength or hyperspectral LIDAR systemenabled by the laser based light source could be configured to detectthe change in relative intensity or amplitude between the firstwavelength and the second wavelength to determine information about theabsorption of the medium or material that the emission is transmittedthrough. That is, the reduction ratio of the first wavelength returnsignal to transmitted signal may be different than the reduction ratioof the second wavelength return signal to the transmitted signal. Thedifference between the reduction ratios can be meaningful and used toextract characteristics of the scanned environment. As first a specificexample, since a blue wavelength will have a known lower absorption thana yellow wavelength in water, if the attenuation of the blue wavelengthis less than the attenuation of the yellow wavelength by a correspondingratio that could be pulled from a look-up table, the LIDAR system couldprovide the user with the information that there is moisture in theenvironment and additionally may be able to determine some relativeamount of moisture or water in the environment along with a spatial mapof the moisture in the environment. In a second specific example, thedifferential in scattering characteristics of the first and the secondwavelength within the transmitted signals is used to determine thitherinformation about the medium the transmitted signal is traveling throughand/or the objects and media that the transmitted signals are reflectingoff to generate the return signal.

In the above examples the differential in the detected versustransmitted signal intensities or amplitudes of the multiple wavelengthswithin the laser based light source LIDAR system illumination beam wereused to capture further information or resolution of the system.Additionally, the differential in time of flight or returned pulse shapebetween the multi-wavelengths can be used to determine characteristicsof the environment. As a specific example, as the first and secondwavelengths in the 2-wavelength example propagate any medium other thanpure air, the medium will have slightly different indices of refractionfor the two wavelengths due to dispersion. Since the speed of the lightsignal is determined by the index of refraction the return signals ofthe first and second wavelength could have a delay or offset compared totheir temporal positions upon transmission. This delay or offset couldbe processed to determine the index of refraction difference for the twowavelengths in the LIDAR system, which could then be related to alibrary or look-up table of media that would have such an indexdifference for the two wavelengths in the LIDAR system. Of course, thisis just one example and is not intended to be limiting or exclude anyother examples of expected benefits from the multi-wavelength LIDARsystem.

In the above examples the differential in the detected versustransmitted signal intensities or amplitudes of the multiple wavelengthswithin the laser based light source LIDAR system was dictated bydispersive properties and absorption properties. Additionally, thedifferential in time of flight or returned pulse shape between themulti-wavelengths can be used to determine characteristics of theobjects for which the LIDAR sensing light is reflecting from. As aspecific example, as the first and second wavelengths in the2-wavelength example propagate any medium other than pure air, themedium will have slightly different MIE scattering properties due theirdifferent wavelengths. The differences in scattering will lead todifferences in return amplitude, which could then be used to calculateand determine differences in the particles from which the scattering isoccurring. In an example the scattering is MIE scattering.

In addition to differential sensing described above, there are manyapplications and system configurations wherein the multi-wavelength orhyperspectral illumination sensing signal in the LIDAR system enabled bythe laser-based light source. In one simple example, multiplewavelengths are used for redundancy and increased accuracy. That is, byusing two or more wavelengths with separated detection, two or moredistinct 3D images can be created of the scanned environment. Byprocessing of these multiple images to compare and contrast the variousfeatures detected, a single integrated 3D image of greater accuracy canbe generated.

FIG. 28 illustrates an exemplary mobile machine using a multi-wavelengthLIDAR system according to an embodiment of the present invention. Inthis example, the laser illumination source comprising a gallium andnitrogen containing laser diode with a first peak wavelength is used forat least one of the multiple LIDAR sensing wavelengths. In the specificexample shown in FIG. 28 the first peak wavelength primary emission fromthe laser diode is a blue emission. Additionally, in this example, thewavelength converted secondary emission with a second peak wavelength isused for at least one of the multiple LIDAR sensing wavelengths. In thespecific example shown in FIG. 28 this second peak wavelength emissionfrom the laser diode is a yellow emission. As described above, bydeploying more than one wavelength for LIDAR sensing and mapping theLIDAR system can benefit in several ways including an increasedfunctionality, increased sensitivity, increased resolution, or other.

It is to be appreciated that it is the extremely high luminance of laserbased light sources that use wavelength conversion members such asphosphor to be used in such LIDAR applications. That is, lasers bythemselves are typically used in LIDAR systems largely due to their highdirectionality, low attenuation, and extreme luminance. The emissioncharacteristics enable the laser emission to be highly collimated tomaintain a controlled beam to accurately and densely survey theenvironment over large distances (i.e. 10 m to 10,000 m). Otherillumination sources such as LEDs are simply not capable of suchluminance requirements to enable the collimation and directionality.However, advanced laser based lighting systems using high power lasersto illuminate tiny spots on phosphors and generate approximately 300 to3,000 lumens, or more, of light from a spot size [optical aperture] of50 μm to 1000 μm enable extreme collimation even though the emissionfrom the phosphor or wavelength conversion member may be Lambertian.That is, in such a laser based lighting system the optical beam can becollimated to less than 1 degree, less than 2 degrees, or less than 5degrees to enable the directionality and intensity required in LIDARapplications. In some examples of all the embodiments described herein,certain and separate optics may be used for the LIDAR system compared tothe lighting or illumination system. For example, a hybrid optic couldbe used to enable a center beam collimation that is separate from theouter beam collimation. The center beam collimation may be a highercollimation such as less than 1 or 2 degrees to serve as the primaryLIDAR transmission beam collimator. The outer beam collimation may be alower collimation such as less than 15 degrees, less than 10 degrees, orless than 5 degrees and serve as the primary illumination beamcollimator. Of course, this is just merely one example of how theoptical system could be designed to separately optimize the LIDARtransmission beam of light from the lighting system lightingcharacteristics.

In some embodiments according to the present invention the integratedlaser based illumination and LIDAR system onboard a mobile machine couldbe supplemented with an additional LIDAR system such as a conventionalLIDAR system that could include a scanning laser operating in theinfrared region. The additional LIDAR system could be configuredseparately from the laser illumination system, but within the samemobile machine. In this embodiment, the additional LIDAR system would bedeployed in conjunction with the integrated laser based illumination andLIDAR system such that an increased functionality, sensitivity, range,scanning area, redundancy, or safety could be achieved by the mobilemachine. For example, a LIDAR system with a more conventional peakwavelength such as about 905 nm, 9XX nm, 1000 nm, 1064 nm, 1300 nm, orabout 1550 nm could be deployed in the additional LIDAR system tocompliment the first peak wavelength from the gallium and nitrogencontaining laser diode in the laser based illumination system such as ablue or violet wavelength. The additional LIDAR system could be used asthe primary 3D mapping apparatus functioning to generate a wide anglemap of the surroundings and the laser based illumination system LIDARcould be used to add mapping information to specified locations, such astoward the front of the mobile machine where the headlights illuminate.Of course, differential detection schemes could be deployed where thedifferences in mapping characteristics between the two LIDAR systemsusing different wavelengths for sensing and mapping could be used tocalculate more comprehensive information and data describing thesurrounding area and environment.

In yet another embodiment an additional laser such as an infrared laserdiode could be included in the laser based illumination system for LIDARmapping. In this embodiment the added laser diode would function toprovide a high performance LIDAR scanning source and would be integrateddirectly into the laser based illumination system. In one example theadded laser diode would be an InP or GaAs laser diode operable at awavelength of about 9XX nm, or about 1,000 nm, or about 1300 nm, orabout 1550 nm. In one preferred embodiment the wavelength is about 1550nm for eye safety purposes. Since in this example the added laser is inthe infrared wavelength regime the emission produced by added laserwould not be visible, and hence would not interfere with theillumination characteristics of the laser based illumination system. Theadditional LIDAR scanning laser could be integrated into the laserillumination system in several configurations. As described previouslyin this invention, the laser based illumination source may be comprisedof multiple laser diodes and even other light emitting devices such asLEDs. The multiple light sources and lasers could be included in theillumination source for a variety of reasons including an increasedluminous flux, a dynamic spatial patterning, to achieve a better colorquality light laser illumination source, a dynamic color control, or toprovide the transmitted signal in visible light communication.Similarly, according to this embodiment, an additional laser sourcewould be included to provide an a LIDAR mapping wavelength, which couldbe the sole LIDAR mapping wavelength in the system or it could be asupplemental or complimentary LIDAR mapping wavelength to one or moreexisting LIDAR mapping wavelengths, such as the visible wavelength fromthe gallium and nitrogen containing laser diode in the illuminationsystem.

In a preferred embodiment the gallium and nitrogen containing blue orviolet laser diode used for illumination and possibly LIDAR scanning isco-packaged with the second laser source for LIDAR scanning, such as aninfrared laser source. Various co-packaging configurations for themultiple laser sources could be designed and implemented. In somedesigns, the gallium and nitrogen containing laser source would bepackaged in a first primary initial package such as a TO-Can, flatpackage, surface mount package, or other type of package. Similarly, theLIDAR laser source could be packaged in a second primary initial packagesuch as a TO-Can, flat package, surface mount package, or other package.Subsequently the first primary package and the second primary packagecontaining the laser sources would then the packaged in a secondarylarger package that contained interfaces to receive the first and secondprimary packages. The sources would then be optically coupled to thephosphor conversion member and/or LIDAR transmitter components beforeentering into the surrounding environment. In another preferredembodiment, the first gallium and nitrogen containing laser diode chipor chip on submount and the LIDAR laser source such as a GaAs or InPbased laser diode or chip on submount are co-packaged onto a commonsupport member.

Referring back to FIG. 20B, it presents an example laser co-packagingembodiment where a gallium and nitrogen containing laser diode such as ablue laser diode, 1603, intended for illumination and optionally LIDARmapping is configured on an intermediate submount member 1604. Theintermediate submount member 1604 is attached to a surface mount basemember 1601. Also included is a second laser diode, 1605, which isintended for LIDAR mapping and could be an infrared emitting laser diodeattached to an intermediate submount 1606, which is then attached to thesurface mount package base member 1601. In this configuration, both theemission from the gallium and nitrogen containing laser diode, 1608, andthe emission from the infrared laser diode, 1609, are incident on thewavelength conversion member, 1602, which could be a phosphor member. Inalternative configurations, the LIDAR sensing laser emission, 1609, mayfollow a different optical pathway that does not interact with thewavelength converter member, 1602.

In a first embodiment the added infrared laser diode is included in thelaser based illumination system and follows a separate optical pathwaycompared to the gallium and nitrogen containing laser diode emission andis not incident on the wavelength conversion member. FIG. 29 is asimplified schematic diagram of a laser light illumination systemintegrated with a LIDAR system including an additional LIDAR mappinglaser according to the present invention. As shown in the figure, theintegrated system 3100 is configured with a power source 3101 to supplypower to both the LIDAR system and the illumination system (note that insome embodiments separate or multiple power sources could be used) alongwith a processor and control unit 3102 configured to receive power fromthe power supply 3101 and data or signals from the receiver portion 3131of the LIDAR system. Based on external inputs 3190 such as user inputs,sensor inputs, or predetermined inputs to provide specifiedfunctionality and power supplied from the power supply, the processorand control unit 3102 determines appropriate first signal to send to oneor more gallium and nitrogen containing laser diodes 3111. The resultingsignal is configured to drive the current and voltage characteristic ofthe gallium and nitrogen containing laser diode 3111 to generate theappropriate intensity pattern from the laser diode to provideelectromagnetic radiation with a first peak wavelength such as a blue orviolet peak wavelength. A second signal from the processor and controlunit 3102 is sent to a LIDAR mapping laser 3121 with a third wavelengthto generate the desired intensity or frequency pattern for the LIDARscanning function such as short pulse of light for the time of flightcalculation. In one embodiment the both the signals for the illuminationlaser diode 3111 and the LIDAR mapping laser 3121 originate from theprocessor and control unit 3102 as shown in the figure. In a separateembodiment multiple processors and power supplies can be included.

As shown in the FIG. 29, the output electromagnetic radiation at thefirst peak wavelength from the gallium and nitrogen containing laserdiode 3111 and the output at the third peak wavelength from theadditional LIDAR mapping laser 3121 follows two separate optical pathswherein the output at the first peak wavelength is incident on thewavelength conversion member 3112 where at least a fraction of theelectromagnetic radiation with the first peak wavelength is converted toelectromagnetic with a second peak wavelength, such as a yellow peakwavelength. In a preferred embodiment, the resulting light in the laserbased illumination system is a white light. The resulting laser basedillumination light is then conditioned with one or more beam shapingelements 3113 to provide a predetermined collimation, divergence, andpattern. Optionally, a beam steering element can be added to the laserbased illumination system to create a spatially dynamic illumination. Insome embodiments a beam shaping element (not shown) such as acollimating optic is used to collimate the laser light prior toincidence on the wavelength conversion member 3112. Additionally,optical fibers such as glass or polymer fibers or other waveguideelements can be used to transport the laser light from the laser diodeto the wavelength conversion member 3112 to create a remotely pumperconversion.

According to FIG. 29, the second optical path directs theelectromagnetic radiation from the LIDAR mapping laser 3121 with thesecond peak wavelength to the LIDAR through optics for beam shapingand/or steering of the LIDAR sensing laser. In some embodiments acollimating optic such as a lens is used to collimate the laser lightprior to entry in the transmitter module of the LIDAR system.Additionally, optical fibers such as glass or polymer fibers or otherwaveguide elements can be used to transport the laser light from thelaser diode to the LIDAR transmitter module. Before exiting to theoutside environment, the LIDAR system laser light can be properlyconditioned with the appropriate divergence and direction to scan thedesired subject area of the surrounding environment. The target LIDARmapping area can be captured in various ways using optics 3122 includinga dynamic scanner such as a MEMS scanning mirror, a microdisplay such asa DLP, or by simply expanding or shaping the beam using basic opticssuch as lens, mirrors, and diffusing elements. Once all of the signaland beam conditioning is completed, the LIDAR beam is projectedexternally where it reflects and scatters off of the various objects inthe surrounding environment and fractionally returns to the receivermodule 3131 of the LIDAR system. The receiver module 3131 is comprisedof some receiver optical components 3132, a detection member such as aphotodiode, a photodiode array, a CCD array, an antenna array, ascanning mirror or microdisplay coupled to a photodiode or other. Thedetected signals in the receiver module 3131 are then used to calculatea time of flight for the transmitted and detected LIDAR signal such as apulse. The calculations or processing to determine the time of flightand the spatial map can be done directly in the receiver or often it isdone in the separate processor unit 3102.

In a second embodiment including an additional laser designated forLIDAR mapping such as an added infrared laser diode, the additionallaser for LIDAR mapping follows a common optical pathway compared to thegallium and nitrogen containing laser diode emission and is not incidenton the wavelength conversion member 3112. As shown in FIG. 30 below inanother embodiment, the output electromagnetic radiation at the firstpeak wavelength from Ga and N based laser diode 3211 and the outputelectromagnetic radiation from the LIDAR mapping laser 3221 at the thirdpeak wavelength is incident on the wavelength conversion member 3231. Atleast a fraction of the electromagnetic radiation with the first peakwavelength such as a blue wavelength is converted to electromagneticwith a second peak wavelength, such as a yellow peak wavelength. In apreferred embodiment, the resulting visible color of light generated inthe laser based illumination system is a white light. Theelectromagnetic emission intensity with the third peak wavelength suchas an infrared peak wavelength would be largely preserved when incidenton the wavelength conversion member. That is, the losses of the lightthrough processes such as absorption would be fractional or minimizedsuch that most of the incident light would simply be reflected orscattered from the wavelength conversion member materials or surfaceswhere it can then be collimated and directed toward the environment forscanning. Some losses of the infrared light would be expected andtolerated, but it is believed that systems with very low loss to theinfrared light resulting from interaction with the phosphor could berealized. Essentially, the resulting emission spectrum would becomprised of light at the first peak wavelength, the second peakwavelength, and the third peak wavelength, wherein the light at thefirst and second peak wavelength would create a visible white light forillumination and the light at the third peak wavelength could beinvisible to the human eye and serve for LIDAR mapping. The resultinglaser based illumination light and LIDAR scanning light is thenconditioned with one or more beam shaping elements to provide apredetermined collimation, divergence, and pattern.

According to the embodiment shown in the FIG. 30, the infrared laser3221 would be electronically driven with an amplitude or frequencymodulation to generate a LIDAR sensing signal, such as pulses of lightinvisible to the eye. The gallium and nitrogen containing laser diode3211 could be driven in a variety of ways including in a continuouswave, quasi-continuous wave, pulsed width modulated, frequencymodulated, or amplitude modulated, or other. Both the infrared lightfrom LIDAR sensing or mapping laser 3221 and the visible light from thediode 3211 would be fed through a common or at least a partially commonoptical pathway prior to entering the environment Optionally, a beamsteering device 3233 could be included such as a MEMS mirror or a DLPmicro-display. Once all of the signal and beam conditioning iscompleted, the LIDAR beam is projected externally where it reflects andscatters off of the various objects in the surrounding environment andfractionally returns to the receiver module of the LIDAR system. Areceiver module is comprised of some receiver optical components 3241, adetection member 3242 such as a photodiode, a photodiode array, a CCDarray, an antenna array, a scanning mirror or microdisplay coupled to aphotodiode or other. The detected signals in the receiver module arethen used to calculate a time of flight for the transmitted and detectedLIDAR signal such as a pulse. The calculations or processing todetermine the time of flight and the spatial map can be done directly inthe receiver or often it is done in the separate processor unit 3202. Inthis embodiment it is possible for both the infrared and the visiblelight to be used for LIDAR mapping.

In an alternative embodiment including an infrared laser wavelength anda visible laser wavelength, the optical pathway for the illuminationsource and the LIDAR sensing and mapping source can be separated. Asseen in the FIG. 31, the optical pathways for the laser lightillumination emission and the LIDAR scanning emission could optionallybe separated wherein the LIDAR scanning emission could be fed throughfurther LIDAR transmission components 3351 for signal shaping, beamshaping, beam steering which could be active beam steering with a MEMSor other, filtering, etc before the emission exits the final optics intothe environment for scanning. The laser illumination optical pathwaycould include further optics 3341 for beam shaping, and optionally, abeam steering element 3342 to create a spatially dynamic illumination.In some embodiments an additional beam shaping element such as acollimating optic is used to collimate the laser light prior toincidence on the wavelength conversion member 3331.

According to the FIG. 31, the combined primary emission from the laserdiode 3311 and the secondary emission from the wavelength convertermember 3331 could be split into 2 pathways by a beam shaping optics 3332for separate conditioning and steering possibilities for the LIDARsystem and illumination system. As described previously, an opticalmodulator could be included within the LIDAR transmitter 3351 togenerate a pulse or other optical signal required for the desired LIDARfunction. The target LIDAR mapping area can be captured in various waysincluding a dynamic scanner such as a MEMS scanning mirror, amicrodisplay such as a DLP, or by simply expanding or shaping the beamusing basic optics such as lens, mirrors, and diffusing elements. Onceall of the signal and beam conditioning is completed, the LIDAR beam isprojected externally where it reflects and scatters off of the variousobjects in the surrounding environment and fractionally returns to thereceiver module of the LIDAR system. The receiver module is comprised ofsome receiver optical components 3361, a detection member 3362 such as aphotodiode, a photodiode array, a CCD array, an antenna array, ascanning mirror or microdisplay coupled to a photodiode or other. Thedetected signals in the receiver module are then used to calculate atime of flight for the transmitted and detected LIDAR signal such as apulse. The calculations or processing to determine the time of flightand the spatial map can be done directly in the receiver or often it isdone in the separate processor unit 3302.

Specific embodiments of this invention employ a transferred gallium andnitrogen containing material process for fabricating laser diodes orother gallium and nitrogen containing devices enabling benefits overconventional fabrication technologies. This unique semiconductor devicemanufacturing technology enables for single-chip integration of multiplesemiconductor materials, which can allow for the integration of variouswavelength laser diodes on the same chip such as visible laser diodesand infrared laser diodes. In one embodiment according to the presentinvention, the laser source in the laser illumination and LIDAR systemis manufactured according to this lift-off and transfer process. In oneexample, laser materials with different visible wavelengths, such asdifferent blue wavelengths, violet wavelengths, and other visiblewavelengths are transferred and formed into lasers on the same carriermember to create a multiple visible wavelength laser source, which couldhave added benefits to the system. Such added benefits include bettercolor quality in the illumination white light, better LIDAR detectionusing differential detection, or lower cost and smaller size. In anotherexample, laser materials with visible wavelengths, such as bluewavelengths, violet wavelengths, and other visible wavelengths aretransferred to the same carrier member as laser material with infraredwavelengths such as 8XX nm, 9XX nm, about 1,000 nm, 1300 nm, or about1550 nm and formed into lasers to create an integrated laser sourcecontaining both visible wavelengths and infrared wavelengths, whichcould have added benefits to the system. Such added benefits includelower cost systems, smaller systems, and better LIDAR detection usingdifferential detection.

In yet another example of a laser based illumination and LIDAR system,the fabrication technology including transfer of epitaxial material canbe used to integrate electronics or other devices into the laser sourcechip. For example, GaN or GaAs based electronics could be included tocreate integrated driver electronics with the light sources. Integratedscanning mirrors can be included. In other examples, silicon electronicscan be included. All of the technologies and devices included in U.S.Pat. Nos. 9,666,677 and 9,379,525) can apply to the integrated LIDARsystem in this invention by reference.

In several preferred embodiments of the laser based smart lightinginvention, the laser based light source is configured for communication.The communication could be intended for biological media such as humanssuch as pedestrians, consumers, athletes, police officers and otherpublic servants, military, travelers, drivers, commuters, recreationactivities, or other living things such as animals, plants, or otherliving objects. The communication could also be intended for objectssuch as cars or any type of auto including autonomous examples,airplanes, drones or other aircraft, which could be autonomous, or anywide range of objects such as street signs, roadways, tunnels, bridges,buildings, interior spaces in offices and residential and objectscontained within, work areas, sports areas including arenas and fields,stadiums, recreational areas, and any other objects or areas. In somepreferred embodiments the smart light source is used in Internet ofThings (IoT), wherein the laser based smart light is used to communicatewith objects such as household appliances (i.e., refrigerator, ovens,stove, etc), lighting, heating and cooling systems, electronics,furniture such as couches, chairs, tables, beds, dressers, etc.,irrigation systems, security systems, audio systems, video systems, etc.Clearly, the laser based smart lights can be configured to communicatewith computers, smart phones, tablets, smart watches, augmented reality(AR) components, virtual reality (VR) components, games including gameconsoles, televisions, and any other electronic devices.

According to some embodiments of the present invention, the laser lightsource can communicate with various methods. In one preferred method,the smart light is configured as a visible light communication (VLC)system such as a LiFi system wherein at least one spectral component ofthe electromagnetic radiation in the light source is modulated to encodedata such that the light is transmitting data. In some examples, aportion of the visible spectrum is modulated and in other examples anon-visible source such as a infrared or ultraviolet source is includedfor communication. The modulation pattern or format could be a digitalformat or an analog format, and would be configured to be received by anobject or device. In some embodiments, communication could be executedusing a spatial patterning of the light emission from the laser basedsmart light system. In an embodiment, a micro-display is used topixelate or pattern the light, which could be done in a rapid dynamicfashion to communicate continuously flowing information or wherein thepattern is periodically changed to a static pattern to communicate astatic message that could be updated. Examples of communication could beto inform individuals or crowds about upcoming events, what is containedinside a store, special promotions, provide instructions, education,sales, and safety. In an alternative embodiment, the shape or divergenceangle of the emission beam is changed to a spotlight from a diffuselight or vice versa using a micro-display or a tunable lens such as aliquid crystal lens. Examples of communication could be to direct anindividual or crowd, to warn about dangers, educate, or promote. In yetanother embodiment of laser light based communication, the color of thesmart lighting system could be changed from a cool white to a warmwhite, or even to a single color such as red, green, blue, or yellow,etc.

In general, laser spectra full widths at half max (FWHM) are verynarrow, with even high-power devices with many lateral modesparticipating in lasing having spectra less than 2 nm wide. Blue LEDstypically have FWHMs of 20 nm or more. The narrow width of laser andSLED spectra is advantageous in that very narrow notch filters can beused to separate the laser spectrum from that emitted by the phosphor.More importantly, such narrow spectra allow for a type of wavelengthdivision multiplexing (WDM) where the VLC emitter is comprised bymultiple laser sources illuminating a phosphor. The VLC emitter thenemits a spectrum consisting of the broad phosphor emission plus theemission from the multiple lasers wherein the lasers could have slightlydifferent wavelengths and be used as separate communication channels. Asan example, the VLC receiver for such a VLC light engine could comprisemultiple detectors, each with a “notch” or “band-pass” filtercorresponding to the various wavelengths of light in the spectrum fromthe emitter. Each detector in the VLC receiver, then, collects lightfrom a corresponding laser provided in the VLC light engine, and due tothe narrowness of the laser light spectrum there is minimal interferencebetween the laser sources and minimal loss of the laser power at thecorresponding detector due to the notch-filters. Such a configuration isadvantageous in that it increases the bandwidth of the VLC light engineproportionally to the number of laser devices. In other embodiments, asingle detector can be used with a dynamic filtering function thatsequentially tunes for each wavelength communication channel.

It is to be understood that in embodiments, the VLC light engine is notlimited to a specific number of laser devices. In a specific embodiment,the light engine includes a single laser device acting as a “pump”light-source, and which is either a laser diode or SLED device emittingat a center wavelength between 390 run and 480 nm. Herein, a “pump”light-source is a laser diode or SLED device that illuminates aswavelength converting element such that a part or all of the laser lightfrom the laser diode or SLED device is converted into longer wavelengthlight by the wavelength converting element. The spectral width of thepump light-source is preferably less than 2 nm, though widths up to 20inn would be acceptable. In another embodiment, the VLC light engineconsists of two or more laser or SLED “pump” light-sources emitting withcenter wavelengths between 380 nm and 480 nm, with the centerwavelengths of individual pump light sources separated by at least 5 nm.The spectral width of the laser light source is preferably less than 2nm, though widths up to 75% of the center wavelength separation would beacceptable. The pump light source illuminates a phosphor which absorbsthe pump light and remits a broader spectrum of longer wavelength light.Each pump light source is individually addressable, such that they maybe operated independently of one another and act as independentcommunication channels.

Encoding of information for communication by the laser or SLED can beaccomplished through a variety of methods. Most basically, the intensityof the LD or SLED could be varied to produce an analog or digitalrepresentation of an audio signal, video image or picture or any type ofinformation. An analog representation could be one where the amplitudeor frequency of variation of the LD or SLED intensity is proportional tothe value of the original analog signal.

A primary benefit of the present invention including a laser diode-basedor SLED-based lighting systems is that both laser diodes and SLEDsoperate with stimulated emission wherein the direct modulation rates arenot governed by carrier lifetime such as LEDs, which operate withspontaneous emission. Specifically, the modulation rate or frequencyresponse of LEDs is inversely proportional to the carrier lifetime andproportional to the electrical parasitics [i.e., RC time constant] ofthe diode and device structure. Since carrier lifetimes are on the orderof nanoseconds for LEDs, the frequency response is limited to the MHzrange, typically in the 100 s of MHz [i.e., 300-500 MHz]. Additionally,since high power or mid power LEDs typically used in lighting requirelarge diode areas on the order of 0.25 to 2 mm², the intrinsiccapacitance of the diode is excessive and can further limit themodulation rate. On the contrary, laser diodes operate wider stimulatedemission wherein the modulation rates are governed by the photonlifetime, which is on the order of picoseconds, and can enablemodulation rates in the GHz range, from about 1 to about 30 GHzdepending on the type of laser structure, the differential gain, theactive region volume, and optical confinement factor, and the electricalparasitics. As a result, VLC systems based on laser diodes can offer10×, 100×, and potentially 1000× higher modulation rates, and hence datarates, compared to VLC systems based on LEDs. Since VLC [ie LiFi]systems in general can provide higher data rates than WiFi systems,laser based LiFi systems can enable 100× to 10,000× the data ratecompared to conventional WiFi systems offering enormous benefits fordelivering data in applications demand high data volumes such as wherethere are a large number of users (e.g., stadiums) and/or where thenature of the data being transferred requires a volume of bits (e.g.,gaming).

To maximize the modulation of response of laser diodes, highdifferential gain, low active region volume, low optical confinement,and low electrical parasitics are desired to enable higher modulationbandwidths. High differential gain can be achieved with optimized activematerial quality and/or with the use of novel materials such as nonpolarand semipolar GaN. Low active region volume can be achieved with activeregion designs comprised of few quantum wells such as 1 to 3 quantumwells and thin such as quantum wells such as thicknesses ranging from 2to 8 nm or from 3 to 6 nm, along with minimized cavity area. To minimizecavity area in edge emitting laser diodes the stripe width and thecavity length can be minimized In conventional high power [i.e.,multi-watt] edge emitting laser diodes the cavity lengths may be longerthan 1 mm and up to or greater than 2 mm and the cavity widths typicallysupport multi-lateral modes with dimensions greater than 3 μm, greaterthan 6 μm, greater than 12 μm, greater than 20 μm, greater than 30 μm,greater than 40 μm, greater than 60 μm, or greater 80 μm. Thesemulti-lateral mode high power GaN based edge emitting laser diodes haverelatively large active areas and thus may have 3 dB frequency responsebandwidth limited to less than 3 GHz, less than 5 GHz or less than 10GHz.

By using narrower cavity or shorter cavity laser architectures, higherbandwidth can be achieved. In some embodiments according to the presentinvention laser diodes with reduced active area are included in thelaser-based smart light device. For example, single lateral modeshort-cavity GaN lasers could be included to serve primary function ofdata transmission along with high power GaN laser to serve primaryfunction of generating white light by exciting one or more wavelengthconversion members.

Vertical cavity surface emitting lasers (VCSELs) are laser diode deviceswherein the optical cavity is orthogonal to the epitaxial growthdirection. These structures have very short cavity lengths dictated bythe epitaxial growth thickness wherein high reflectivity distributedbragg reflectors (DBR) terminating each end of the cavity. The extremelysmall cavity length and hence cavity area of VCSELs makes them ideal forhigh speed modulation, wherein modulation bandwidths of greater than 10GHz, greater than 20 GHz, and greater than 30 GHz are possible. In someembodiments of the present invention VCSELs can be included. Such VCSELsmay be based on GaN and related materials, InP and related material, orGaAs and related materials.

Low RC time constant can be achieved by keeping the diode area small,the thickness of the depletion or intrinsic region large, and minimizedcapacitance contribution from the device structure. Laser diode andother diode devices are comprised of two primary sources of capacitancethat can be modeled as a simple parallel plate capacitor. The first isthe active region itself wherein the active area defines the area of thecapacitor and the depletion width dictates the parallel plate spacing.Thus, reducing the diode area both improves modulation response byreducing photon lifetime and by reducing the capacitance. The secondmajor capacitance contribution comes from electrical bond pad area suchas the anode and/or the cathode. To minimize this parasitic capacitance,bond pads and other electrical features should be design carefully tominimize area and increase the spacing of the two charged plates. Alongwith using small bond pad areas thick dielectrics (of about 200 nm to10,000 nm) or low k dielectrics such as benzocyclobutene (BCB),polymethyl methacrylate (PMMA) can be employed below the metal bond padto reduce the capacitance. Or more simply, thickness of conventionaldielectric materials such as SiO₂ or Si_(x)N_(y) can be designed forminimized capacitance. In a preferred embodiment, the epitaxial transfermethod is used to form a GaN based laser diode on a carrier wafer,wherein the carrier wafer is a semi-insulating substrate. Since amajority of the bond pad area is formed on semi-insulating substrate,the capacitance is minimized and should enable increased modulationrates relative to laser diodes formed using conventional fabricationtechnology.

The above description focuses primarily on the direct modulation of thelaser diode source itself, but in other embodiments of the presentinvention separate elements are included to perform the modulation ofthe carrier signal generated by the laser diode. These separate elementsinclude electroabsorption modulators (EAMs), which rely on thepreferential absorption of the carrier signal with reverse bias, orMach-Zhender Interferometers (MZI). The benefits of EAM and MZImodulators include higher modulation rates and negative chirp. Theseparate modulation elements could be monolithically integrated on thesame chip as the laser diode connected by a waveguide using any numberof integration schemes or discretely included as separated chip wherethe optical output of the laser diode would need to be coupled to themodulator. This could be accomplished with free-spacing coupling, withfiber coupling, or with using optics. In some preferred embodiments, thelaser diode and modulator are formed on the same carrier wafer using theepitaxial transfer technology described in this invention to form GaNlaser diodes.

The carrier signal from the laser based light source in this smartlighting invention can be modulated in any available modulation formatto transmit data with visible light communication or LiFi. For example,the modulation can be amplitude modulation (AM) or frequency modulation(FM). Common AM modulation schemes are listed on Wikopedia and include,double-sideband modulation (DSB), double-sideband modulation withcarrier (DSB-WC) (used on the AM radio broadcasting band),double-sideband suppressed-carrier transmission (DSB-SC),double-sideband reduced carrier transmission (DSB-RC), single-sidebandmodulation (SSB, or SSB-AM), single-sideband modulation with carrier(SSB-WC), single-sideband modulation suppressed carrier modulation(SSB-SC), vestigial sideband modulation (VSB, or VSB-AM), quadratureamplitude modulation (QAM). Similarly, common digital modulationtechniques are based on keying including PSK (phase-shift keying) wherea finite number of phases are used, FSK (frequency-shift keying) where afinite number of frequencies are used, ASK (amplitude-shift keying)where a finite number of amplitudes are used, and QAM (quadratureamplitude modulation) where a finite number of at least two phases andat least two amplitudes are used. There are several variations of eachof these listed digital modulation techniques, which can be included inthe invention. The most common variant of ASK is simple on-off keying(OOK). Additional modulation schemes include continuous phase modulation(CPM) methods, minimum-shift keying (MSK), Gaussian minimum-shift keying(GMSK), continuous-phase frequency-shift keying (CPFSK), orthogonalfrequency-division multiplexing (OFDM) modulation, discrete multitone(DMT), including adaptive modulation and bit-loading, and waveletmodulation.

Digital encoding is common encoding scheme where the data to betransmitted is represented as numerical information and then varying theLD or SLED intensity in a way that corresponds to the various values ofthe information. As an example, the LD or SLED could be turned fully onand off with the on and off states correlated to binary values or couldbe turned to a high intensity state and a low intensity state thatrepresent binary values. The latter would enable higher modulation ratesas the turn-on delay of the laser diode would be avoided. The LD or SLEDcould be operated at some base level of output with a small variation inthe output representing the transmitted data superimposed on the baselevel of output. This is analogous to having a DC offset or bias on aradio-frequency or audio signal. The small variation may be in the formof discrete changes in output that represent one or more bits of data,though this encoding scheme is prone to error when many levels of outputare used to more efficiently encode bits. For example two levels may beused, representing a single binary digit or bit. The levels would beseparated by some difference in light output. A more efficient encodingwould use 4 discrete light output levels relative to the base level,enabling one value of light output to represent any combination of twobinary digits or bits. The separation between light output levels isproportional to n−1, where n is the number of light output levels.Increasing the efficiency of the encoding in this way results in smallerdifferences in the signal differentiating encoded values and thus to ahigher rate of error in measuring encoded values.

Return to zero (RZ) and non return to zero (NRZ) protocols are commonvariants of OOK digital encoding formats. Another encoding scheme is toencode binary values into the rising for falling edge of a change in thelight intensity between a low and high value. For example, Manchesterphase encoding (MPE) could be used, where binary values are representedby a rising or falling of the signal intensity between two levels at aparticular point in the cycle of a master clock or timing signal. Thiscan be extended to differential MPE where a binary value is transmittedby either leaving the signal at the beginning of the nth clock cycle thesame as the previous cycle or changing the signal level. There is, then,only one signal level change per clock cycle such that the averageperiod of the signal change can be used to keep in sync with the masterclock. Another example encoding scheme is non-return-to-zero inverted(NRZI), where the signal levels representing ones and zeros will switchto be opposite that of the previous cycle. This ensures a signal levelchange occurs only at the edges of master clock cycles. Of course, anyof these encoding schemes could be expanded to include multipleamplitude levels as in for example pulsed amplitude modulation wherevarious combinations of the timing of a signal transition in the masterclock cycle as well as the signal amplitude are used to encode multiplebits of data.

An alternative is to superimpose a periodic signal on the base level, asine or cosine for example, and then encode binary values by shiftingone or more of the amplitude, frequency or phase of the signal. Thiswould be equivalent of amplitude modulation (AM), frequency modulation(FM) and phase modulation in radio transmission encoding schemes.Another possibility is to combine multiple periodic signals of the sameperiod but out of phase and vary both the amplitude and phase shiftbetween the two signals such that combinations of amplitude and phaseshift represent various combinations of bit values. For example a systemwith two values of amplitude and phase shift could encode a two-bit,binary sequence; i.e. 00, 01, 10, 11. Other encoding schemes arepossible. Superimposing a small signal on a base level of output has theadvantage that the time average power of the small signal relative tothe base level can be kept near or at zero such that the apparentbrightness to the eye of the emitter will be dominated by the base levelof output rather than the signal. In the PWM encoding scheme or anyscheme where the emitter is modulated over a significant portion of itsoutput range the apparent brightness of the device will vary dependingon the data transmitted; e.g. transmitting all zeros or all ones willlead to an emitter that is either mostly on or off. In otherembodiments, coherent detection schemes are used to detect the datastream from the laser diode based VLC systems.

Multiplexing, or combining of multiple analog message signals or digitaldata streams into a single signal over a shared medium. It is possibleto combine laser or SLED light sources in an embodiment of thisinvention such that the individual signals from the plurality of lightsources can be differentiated at the receiver. One method of this wouldbe wavelength division multiplexing (WDM). As mentioned in previouslydescribed embodiments, multiple laser or SLED light sources could becombined in a single light engine with center wavelengths chosen to beseparated sufficiently that narrow, optical band-pass or “notch” filterscould be used at the VLC receiver to filter out the majority of light atwavelengths not corresponding to an individual laser or SLED device.

In an example embodiment, a light engine contains 3 blue lasers actingas pump light sources emitting spectra with FWHMs of 2 nm and centerwavelengths of 440, 450 and 460 nm. These pump light sources illuminatea wavelength converting element which absorbs part of the pump light andreemits a broader spectrum of longer wavelength light. The light engineis configured such that both light from the wavelength convertingelement and the plurality of light sources are emitted from thelight-engine. Each pump light source is independently addressable, andis controlled by a laser driver module configured to generatepulse-modulated signal at a frequency range of about 50 to 500 MHz, 500MHz to 5 GHz, 5 GHz to 20 GHz, or greater than 20 GHz. The data transferbandwidth of the light engine is three times larger than that of a lightengine with one laser pump light source. A properly configured VLCreceiver would be able to receive data independently and simultaneouslyon the 440, 450 and 460 nm communication channels. For example, a VLCreceiver may detect VLC signals using three photodetectors capable ofmeasuring pulse-modulated light signals at a frequency range of about 50to 300 MHz, 500 MHz to 5 GHz, 5 GHz to 20 GHz, or greater than 20 GHz.The light entering each photodetector is filtered by a narrow band-passfilter (band pass width less than 10 nm) and center wavelength centeredon the emitted wavelength of either 440, 450 or 460 nm. It should beunderstood that this example embodiment should not be limiting of thenumber of blue pump laser devices or their distribution of center pointwavelengths. For example, in a specific embodiment the device may have2, 3, 4, 5 or more pump light sources with center point wavelengthsspanning the range of 400 nm to 470 nm. In alternative preferredembodiments, the device may have 6 or more, 12 or more, 100 or more, or1000 or more laser diode or SLED pump light sources, where some or allof the laser diode or SLED devices could be operated as a discretecommunication channel to scale the aggregate bandwidth of thecommunication system.

In an embodiment, multiplexing is achieved by varying the polarizationdirection of light emitted from two or more laser or SLED light sources.Light emitted from a laser or SLED can be highly polarized, such thatmultiple lasers or SLEDs in a light engine could be configured such thatwhen emitted from the light engine separate data communication channelshave different polarization directions. A VLC receiver with polarizationfilters could distinguish signals from the two channels and therebyincrease the bandwidth of the VLC transmission.

FIG. 32A shows a functional block diagram for a basic laser diode basedVLC-enabled laser light source or “light engine” that can function as awhite light source for general lighting and display applications andalso as a transmitter for visible light communication such as LiFi.Referring to FIG. 32A, the white light source includes three subsystems.The first subsystem is the light emitter 1509, which consists of eithera single laser device or a plurality of laser devices (1503, 1504, 1505and 1506). The laser devices are configured such that the laser lightfrom each laser device is incident on a wavelength converting element1507 such as a phosphor which absorbs part or the entirety of the laserlight from one or more laser devices and converts it into a broaderspectrum of lower energy photons. The second subsystem is the controlunit 1510, which includes at least a laser driver 1502 and a VLC modem1501. The laser driver 1502 powers and modulates the all laser devices(1503, 1504, 1505 and 1506) to enable them for visible lightcommunications. Optionally, the laser driver 1502 at least can drive onelaser device independently of the rest. The VLC modem 1501 is configuredto receive digitally encoded data from one or more data sources (wiredor wirelessly) and convert the digitally encoded data into analogsignals which determine the output of the laser driver 1502. Themodulation of the laser light by the laser driver based on the encodeddata can be either digital, with the emitted power of the laser beingvaried between two or more discrete levels, or it can be based on thevariation of the laser intensity with a time-varying pattern where datais encoded in the signal by way of changes in the amplitude, frequency,phase, phase-shift between two or more sinusoidal variations that aresummed together, and the like.

In some preferred embodiments the output of the laser driver isconfigured for a digital signal. The third subsystem is an optional beamshaper 1508. The light emitted from the wavelength converting element1507 (which absorbed the incident laser light) as well as unabsorbed,scattered laser light passes through the beam shaper 1508 which directs,collimates, focuses or otherwise modifies the angular distribution ofthe light. After the beam shaper 1508 the light is formulated as acommunication signal to propagate either through free-space or via awaveguide such as an optical fiber. The light engine, i.e., thelaser-based white light source is provided as a VLC-enabled lightsource. Optionally, the beam shaper 1508 may be disposed prior to thelight incident to the wavelength converting element 1507. Optionally,alternate beam shapers are disposed at optical paths both before andafter the wavelength converting element 1507.

In some embodiments, additional beam shapers would be included betweenthe laser diode members and the wavelength converter element toprecondition the pump beam before it is incident on the phosphor. Forexample, in a preferred embodiment the laser or SLED emission would becollimated prior to incidence with the wavelength converter such thatthe laser light excitation spot would have a specified and controlledsize and location.

For a single laser based VLC light source, this configuration offers theadvantage that white light can be created from combination of alaser-pumped phosphor and the residual, unconverted blue light from thelaser. When the laser is significantly scattered it will have aLambertian distribution similar to the light emitted by the wavelengthconverting element, such that the projected spot of light has uniformcolor over angle and position as well as power of delivered laser lightthat scales proportionally to the white light intensity. For wavelengthconverting elements that do not strongly scatter laser light, the beamshaping element can be configured such that the pump and down convertedare collected over similar areas and divergence angles resulting in aprojected spot of light with uniform color over angle, color overposition within the spot, as well as power of delivered laser light thatscales proportionally to the white light intensity. This embodiment isalso advantageous when implemented in a configuration provided withmultiple pump lasers in that it allows for the pump laser light from theplurality of lasers to be overlapped spatially on the wavelengthconverting element to form a spot of minimal size. This embodiment isalso advantageous in that all lasers can be used to pump the wavelengthconverting element-assuming the lasers provided emit at wavelengthswhich are effective at pumping the wavelength converting element-suchthat power required from any one laser is low and thus allowing foreither use of less-expensive lower-power lasers to achieve the sametotal white light output or allowing for under-driving of higher-powerlasers to improve system reliability and lifetime.

FIG. 32B shows another functional diagram for a basic laser diode basedVLC-enabled light source for general lighting and display applicationsand also as a transmitter for visible light communication. Referring toFIG. 32B, the white light source includes three subsystems. The firstsubsystem is the light emitter 1530, which consists of a wavelengthconverting element 1527 and either a single laser device or a pluralityof laser devices 1523, 1524, 1525 and 1526. The laser devices areconfigured such that the laser light from a subset of the laser devices1523 and 1524 is partially or fully converted by the wavelengthconverting element 1527 into a broader spectrum of lower energy photons.Another subset of the laser devices 1525 and 1526 is not converted,though they may be incident on the wavelength converting element. Thesecond subsystem is the control unit 1520 including at least a laserdriver 1522 and a VLC modem 1521. The laser driver 1522 is configured topower and modulate the laser devices. Optionally, the laser driver 1522is configured to driver at least one laser device independently of therest among the plurality of laser devices (e.g., 1523, 1524, 1525 and1526). The VLC modem 1521 is configured to couple (wired or wirelessly)with a digital data source and to convert digitally encoded data intoanalog signals which determine the output of the laser driver 1522. Thethird subsystem is an optional beam shaping optical element 1540. Thelight emitted from the wavelength converting element 1527 as well asunabsorbed, scattered laser light passes through the beam shapingoptical element 1540 which directs, collimates, focuses or otherwisemodifies the angular distribution of the light into a formulated visiblelight signal.

In some embodiments, additional beam shapers would be included betweenthe laser diode members and the wavelength converter element toprecondition the pump light beam before it is incident on the phosphor.For example, in a preferred embodiment the laser or SLED emission wouldbe collimated prior to incidence with the wavelength converter such thatthe laser light excitation spot would have a specified and controlledsize and location. The light signal then leaves the light engine andpropagates either through free-space or via a waveguide such as anoptical fiber. In an embodiment, the non-converted laser light isincident on the wavelength converting element 1527, however thenon-converted laser light is efficiently scattered or reflected by thewavelength converting element 1527 such that less than 10% of theincident light is lost to absorption by the wavelength convertingelement 1527.

This embodiment has the advantage that one or more of the datatransmitting lasers is not converted by the wavelength convertingelement. This could be because the one or more lasers are configuredsuch that they are not incident on the element or because the lasers donot emit at a wavelength that is efficiently converted by the wavelengthconverting element. In some examples, the non-converted light might becyan, green or red in color and may be used to improve the colorrendering index of the white light spectrum while still providing achannel for the transmission of data. Because the light from theselasers is not converted by the wavelength converting element, lowerpower lasers can be used, which allows for lower device costs as well asenabling single lateral optical mode devices which have even narrowerspectra than multi-mode lasers. Narrower laser spectra would allow formore efficient wavelength-division multiplexing in VLC light sources.

Another advantage is that the lasers that bypass the wavelengthconverting element may be configured to allow for highly saturatedspectra to be emitted from the VLC capable light source. For example,depending on the wavelength converting element material andconfiguration, it may not be possible to have a blue laser incident onthe wavelength converting element that is not partially converted tolonger wavelength light. This means that it would be impossible to usesuch a source to produce a highly saturated blue spectrum as there wouldalways be a significant component of the emitted spectrum consisting oflonger wavelength light. By having an additional blue laser source,which is not incident on the wavelength converting element, such asource could emit both a white light spectrum as well as a saturatedblue spectrum. Addition of green and red emitting lasers would allow thelight source to emit a white light spectrum by down conversion of a blueor violet pump laser as well as saturated, color-tunable spectra able toproduce multiple spectra with color points ranging over a wide area ofthe color gamut.

Referring back to FIGS. 19A, 19B, 20A, 20B, and 20C, showing severalembodiments of the VLC-enabled solid-state white light source in a SMDtype package. Optionally, the wedge-shaped members 1401, 1604, 1614, and1616 in the SMD package are configured such that the laser light fromeach of multiple laser devices is incident on the wavelength convertingelement 1406 or 1602 with an angle of 10 to 45 degrees from the plane ofthe wavelength converting element's upper. Optionally, the wavelengthconverting element 1602 is bonded to the common substrate 1601 using asolder material. Optionally, the bonded surface of the wavelengthconverting element 1602 is provided with an adhesion promoting layersuch as a Ti/Pt/Au metal stack. Optionally, the adhesion promoting layerincludes as first layer that is highly reflective. Optionally, theadhesion promoting layers could be Ag/Ti/Pt/Au, where Ag is adjacent tothe wavelength converting element and provides a highly-reflectivesurface below the wavelength converting element. The laser devices areconnected electrically to the backside solder pads using wire bondingbetween electrical contact pads on the laser device chips and thetop-side wire-bond pads on the common substrate. Optionally, only one ofthe multiple laser devices in the SMD packaged white light source is ablue pump light source with a center wavelength of between 405 and 470nm. Optionally, the wavelength converting element is a YAG-basedphosphor plate which absorbs the pump light and emits a broader spectrumof yellow-green light such that the combination of the pump lightspectra and phosphor light spectra produces a white light spectrum. Thecolor point of the white light is preferably located within du‘v’ ofless than 0.03 of the Planckian blackbody locus of points. Optionally,one of the multiple laser devices is a green light emitting laser diodewith a center wavelength between 500 and 540 nm and one of the multiplelaser devices is a red light emitting laser diode with a centerwavelength ranging between 600 and 650 nm. Addition of diffuselyreflected red and green laser light to the spectrum of thephosphor-based wavelength converting element and the blue pump laserdevice results in a white light source with dynamically adjustable colorpoint as well as the capacity to transmit data simultaneously andindependently by wavelength division multiplexing of the three lasersources of different center wavelengths.

Use of multiple lasers of same wavelength allows for running each laserat a lower power than what one would do with only one pump laser for afixed power of emitted white light spectrum. Addition of red and greenlasers which are not converted allow for adjusting the color point ofthe emitted spectrum. Given a single blue emitter, so long as theconversion efficiency of the wavelength converting element does notsaturate with pump laser intensity, the color point of the white lightspectrum is fixed at a single point in the color space which isdetermined by the color of the blue laser, the down-converted spectrumemitted by the wavelength converting element, and the ratio of the powerof the two spectra, which is determined by the down-conversionefficiency and the amount of pump laser light scattered by thewavelength converting element. By the addition of an independentlycontrolled green laser, the final color point of the spectrum can bepulled above the Planckian blackbody locus of points. By addition of anindependently controlled red laser, the final color point of thespectrum can be pulled below the Planckian blackbody locus of points. Bythe addition of independently controlled violet or cyan colored lasers,with wavelengths not efficiently absorbed by the wavelength convertingelement, the color point can be adjusted back towards the blue side ofthe color gamut. Since each laser is independently driven, thetime-average transmitted power of each laser can be tailored to allowfor fine adjustment of the color point and CRI of the final white lightspectrum.

Optionally, multiple blue pump lasers might be used with respectivecenter wavelengths of 420, 430, and 440 nm while non-converted green andred laser devices are used to adjust the color point of the devicesspectrum. Optionally, the non-converted laser devices need not havecenter wavelengths corresponding to red and green light. For example,the non-converted laser device might emit in the infra-red region atwavelengths between 800 nm and 2 microns. Such a light engine would beadvantageous for communication as the infra-red device, while not addingto the luminous efficacy of the white light source, or as a visiblelight source with a non-visible channel for communications. This allowsfor data transfer to continue under a broader range of conditions andcould enable for higher data rates if the non-visible laser configuredfor data transmission was more optimally suited for high speedmodulation such as a telecom laser or vertical cavity surface emittinglaser (VCSEL). Another benefit of using a non-visible laser diode forcommunication allows the VLC-enabled white light source to use anon-visible emitter capable of effectively transmitting data even whenthe visible light source is turned off for any reason in applications.

In some embodiments, specialized gallium and nitrogen containing laserdiodes may be included for more optimal VLC functionality. In oneexample a lower power or single lateral mode laser may be included toprovide a higher modulation rate and hence a higher data transmissioncapability. Lower power lasers typically require a reduced active regionvolume and hence shorter photon lifetime and lower parasitic capacitanceenabling higher modulation frequencies. Additional measures can be takensuch as the use of low k dielectrics to reduce capacitance or theelectrodes, the addition of traveling wave type of electrodes, andelectrodes configured for high speed. In one embodiment one or moregallium and nitrogen containing laser diodes configured for datatransmission are included in addition to the primary phosphor excitationlaser diode. The data transmission laser diode is capable of 3 dBmodulation rates higher than 5 GHz, higher than 10 GHz, or higher than20 GHz.

In some embodiments, the white light source is configured to be a smartlight source having a beam shaping optical element. Optionally, the beamshaping optical element provides an optical beam where greater than 80%of the emitted light is contained within an emission angle of 30degrees. Optionally, the beam shaping element provides an optical beamwhere greater than 80% of the emitted light is contained within anemission angle of 10 degrees. Optionally, the white light source can beformed within the commonly accepted standard shape and size of existingMR, PAR, and AR111 lamps. Optionally, the white light source furthercontains an integrated electronic power supply to electrically energizethe laser-based light module. Optionally, the white light source furthercontains an integrated electronic power supply with input power withinthe commonly accepted standards. Of course, there can be othervariations, modifications, and alternatives.

In some embodiments, the smart light source containing at least alaser-based light module has one or more beam steering elements toenable communication. Optionally, the beam steering element provides areflective element that can dynamically control the direction ofpropagation of the emitted laser light. Optionally, the beam steeringelement provides a reflective element that can dynamically control thedirection of propagation of the emitted laser light and the lightemitted from the wavelength converting element. Optionally, the smartlight white light source further contains an integrated electronic powersupply to electrically energize the beam steering elements. Optionally,the smart light white light source further contains an integratedelectronic controller to dynamically control the function of the beamsteering elements.

Smart lighting requires spatial control of the light beam in order toachieve a variety of illumination effects that can be shined in a staticfashion upon demand, or that can be varied with time to produce dynamiclight patterns. The ideal smart lighting spatial beam patterns includebasic matrix light beam illumination capability of 25 pixels, to ahigher resolution of pixels such as VGA 640×480 pixels, to HD 1920×1080pixels, to UHD such as 3840×2160 and 7680×4320. The illumination patternshould be adaptable from a broad high angle floodlight to narrow beamangle spotlight. The illumination module should be highly compact, andhighly efficient by passing more than 50% of the light. The illuminationmodule should be robust, so as to withstand typical mechanical shock andvibration associated with consumer and automotive products.

According to an embodiment, the present invention provides a dynamiclaser-based light source or light projection apparatus including amicro-display element to provide a dynamic beam steering, beampatterning, or beam pixelating affect Micro-displays such as amicroelectromechanical system (MEMS) scanning mirror, or “flyingmirror”, a digital light processing (DLP) chip or digital mirror device(DMD), or a liquid crystal on silicon (LCOS) can be included todynamically modify the spatial pattern and/or color of the emittedlight. In one embodiment the light is pixelated to activate certainpixels and not activate other pixels to form a spatial pattern or imageof white light. In another example, the dynamic light source isconfigured for steering or pointing the light beam. The steering orpointing can be accomplished by a user input configured from a dial,switch, or joystick mechanism or can be directed by a feedback loopincluding sensors.

One approach to achieve dynamic light beam control is with a scanningMEMS mirror that actively steers the laser beam so that the reflectedbeam is incident on different points of the same phosphor assembly, oron different phosphor assemblies. This approach has the advantage ofhigh optical efficiency, with more than 80% of the light being reflectedoff of the MEMS mirror and onto the phosphor for efficientdownconversion. The downconverted light from the phosphor is thencaptured with optics, forming a spatial beam pattern after the opticsthat is varied as the deflection of the MEMS mirror changes. Thescanning MEMS mirror can be based on actuators that are electromagnetic,electrostatic, piezoelectric, or electrothermal, pneumatic, and shapememory alloy. Optionally, the MEMS mirrors for smart lighting wouldproduce high deflection angles more than 10 degrees. Optionally, theMEMS mirrors for smart lighting would be low in power consumption lessthan 100 mW, or even less than 1 mW, with a low driving voltage <5V.Optionally, the MEMS mirrors for smart lighting would have high scanfrequencies capable of producing HD resolution. Optionally, the MEMSmirrors for smart lighting would be robust under shock and vibrationthat are greater than 2000 g. Optionally, the MEMS mirrors for smartlighting would be capable of performing resonant operation for vectorpointing. Optionally, the MEMS mirrors for smart lighting would becapable of providing high reflectivity, i.e., >80% and ideally >99%, forhigh power operation. Optionally, the MEMS mirrors for smart lightingwould be produced by simple fabrication techniques for low cost. Forexample, single biaxial 2D mirror design (instead of 1D mirror design)can be achieved for low cost and simple architecture.

In an embodiment, a MEMS scanning mirror micro-display is included inthe device and is configured to steer a beam of light by reflecting thelight at a predetermined angle that can be dynamically modulated. In oneexample, the MEMS scanning mirror is configured to steer a collimatedbeam of laser excitation light from the one or more laser diodes togenerate a predetermined spatial and/or temporal pattern of excitationlight on the phosphor member. In this example the micro-display isupstream of the wavelength converter member in the optical pathway. Atleast a portion of the wavelength converted light from the phosphormember could then be recollimated or shaped using a beam shaping elementsuch as an optic. In a second example the MEMS is configured to steer acollimated beam of at least a partially wavelength converted light togenerate a predetermined spatial and/or temporal pattern of convertedlight onto a target surface or into a target space. In this example themicro-display is downstream of the wavelength converter member in theoptical pathway. MEMS scanning mirrors or microscanners are configuredfor dynamic spatial modulation wherein the modulatory movement of asingle mirror can be either translatory or rotational, on one or twoaxes. For translation modulation a phase shifting effect to the lighttakes place. For rotational modulation the MEMS scanning mirror isdeflected at an angle determined by the rotational angular position ofthe mirror upon deflection. The deflecting scanning mirror causes anincident light beam to be reflected at an angle based on the degree ofdeflection. Such scanning mirror technology is capable of providing ahigh definition video such as 1080P or 4K resolution to enable crisplydefined spatial patterning of a white light source based on laser diodesand a wavelength converter.

The MEMS microscanning chips included in this invention can havedimensions of less than 1 mm×1 mm, equal to or greater than 1 mm×1 mm,greater than about 3 mm×3 mm, greater than about 5 mm×5 mm, or greaterthan about 10 mm×10 mm wherein the optimum size will be selected basedon the application including the optical power and diameter of thecollimated beam the microscanner is configured to reflect. In someembodiments specialized high reflectivity coatings are used on the MEMSmicroscanner chips to prevent absorption of the light beam within thechip, which can cause heating and failure of the MEMS chip if the poweris too high. For example, the coating material could have a reflectivitygreater than about 95%, greater than about 99%, greater than about99.9%, or greater. The scan frequencies range between from about lessthan 0.1 to greater than 50 kHz wherein deflection movement is eitherresonant or quasi-static. Mechanical deflection angles of themicroscanning devices reach greater than about ±30°, wherein the tiltingmovement can dynamically direct the collimated light over a projectionplane or into a space. The forces used to initiate the microscannerdeflection can include electromagnetic forces, electrostatic forces,thermo-electric forces, and piezo-electric forces.

In the case of electrothermal actuated MEMS mirrors, typically, avoltage is applied to the device, and current flows through it causingheating. When heating occurs to two materials with differentcoefficients of thermal expansion such as a bimetallic device, onematerial expands more than the other, and the actuator bends toaccommodate different deflections depending on the voltage and currentprovided. Another approach is to electrically activate two similar oridentical materials that have different geometrical properties andtherefore different electrical resistances, causing different heatingfor each portion of the device, and resulting in actuator deflection.Such devices can be driven in both resonant and non resonant mode. Whilesuch approaches are rugged and insensitive to shock and vibration andcan be quite simple and elegant to manufacture, they suffer from limitedbandwidth, high power consumption, and inadequate scanning angles.

Another approach is piezoelectric MEMS mirrors, which operate on theprinciple that stress can be induced in a material by an electric fieldthat is applied to the actuator. While such approaches can have fastresponse and high bandwidth and robust operation over shock andvibration, they require high driving voltage and the actuator deflectionangle is difficult to control.

A common MEMS mirror design uses electrostatic actuators which rely on achange in stationary electric fields to generate mechanical motion.These have the advantage of low complexity fabrication, reliableoperation, and low power consumption. However, they have relatively lowtorque and limited bandwidth, are sensitive to shock and vibration, andrequire high driving voltages. Parallel plate approaches are common, butresult in resonant operation and are not capable of vector scanning.Non-resonant mode designs are possible using vertical or rotary combdesigns.

Another common MEMS mirror design uses electromagnetic actuators, whichtypically include coils on the backs of the mirrors interact withpermanent magnetic fields to provide actuation. These designs offer lowvoltage, high bandwidth, and insensitivity to shock and vibration, andprovide large deflection angles, but require higher power consumptionthan other approaches such as electrostatic. A common approach is toutilize resonant mode designs for low complexity fabrication, but thisconstrains the operating mode to be scanned continuously, without thepotential for static beam pointing or vector scanning. Non-resonant modedesigns are used for applications requiring vector scanning, andchallenges include complex fabrication.

According to an embodiment, the present invention provides a dynamiclaser-based light source or light projection apparatus including ahousing having an aperture. The apparatus can include an input interfacefor receiving a signal to activate the dynamic feature of the lightsource. The apparatus can include a video or signal processing module.Additionally, the apparatus includes a light source based on a lasersource. The laser source includes a violet laser diode or blue laserdiode. The dynamic light feature output comprised from a phosphoremission excited by the output beam of a laser diode, or a combinationof a laser diode and a phosphor member. The violet or blue laser diodeis fabricated on a polar, nonpolar, or semipolar oriented Ga-containingsubstrate. The apparatus can include a microelectromechanical system(MEMS) scanning mirror, or “flying mirror”, configured to project thelaser light or laser pumped phosphor white light to a specific locationto the outside world. By rastering the laser beam using the MEMS mirrora pixel in two dimensions can be formed to create a pattern or image.

According to another embodiment, the present invention includes ahousing having an aperture and an input interface for receiving signalssuch as frames of images. The dynamic light system also includes aprocessing module. In an embodiment, the processing module iselectrically coupled to an ASIC for driving the laser diode and the MEMSscanning mirrors.

In an embodiment, a laser driver module is provided. Among other things,the laser driver module is adapted to adjust the amount of power to beprovided to the laser diode. For example, the laser driver modulegenerates a drive current based a pixels from the a signals such asframes of images, the drive currents being adapted to drive a laserdiode. In a specific embodiment, the laser driver module is configuredto generate pulse-modulated signal at a frequency range of about 50 to300 MHz.

In an alternative embodiment, DLP or DMD micro-display chip is includedin the device and is configured to steer, pattern, and/or pixelate abeam of light by reflecting the light from a 2-dimensional array ofmicro-mirrors corresponding to pixels at a predetermined angle to turneach pixel on or off. In one example, the DLP or DMD chip is configuredto steer a collimated beam of laser excitation light from the one ormore laser diodes to generate a predetermined spatial and/or temporalpattern of excitation light on the wavelength conversion or phosphormember. At least a portion of the wavelength converted light from thephosphor member could then be recollimated or shaped using a beamshaping element such as an optic. In this example the micro-display isupstream of the wavelength converter member in the optical pathway. In asecond example the DLP or DMD micro-display chip is configured to steera collimated beam of at least a partially wavelength converted light togenerate a predetermined spatial and/or temporal pattern of convertedlight onto a target surface or into a target space. In this example themicro-display is downstream of the wavelength converter member in theoptical pathway. DLP or DMD micro-display chips are configured fordynamic spatial modulation wherein the image is created by tiny mirrorslaid out in an array on a semiconductor chip such as a silicon chip. Themirrors can be positionally modulated at rapid rates to reflect lighteither through an optical beam shaping element such as a lens or into abeam dump. Each of the tiny mirrors represents one or more pixelswherein the pitch may be 5.4 μm or less. The number of mirrorscorresponds or correlates to the resolution of the projected image.Common resolutions for such DLP micro-display chips include 800×600,1024×768, 1280×720, and 1920×1080 (HDTV), and even greater.

According to an embodiment, the present invention provides a dynamiclaser-based light source or light projection apparatus including ahousing having an aperture. The apparatus can include an input interfacefor receiving a signal to activate the dynamic feature of the lightsource. The apparatus can include a video or signal processing module.Additionally, the apparatus includes a light source based on a lasersource. The laser source includes a violet laser diode or a blue laserdiode. The dynamic light feature output comprised from a phosphoremission excited by the output beam of a laser diode, or a combinationof a laser diode and a phosphor member. The violet or blue laser diodeis fabricated on a polar, nonpolar, or semipolar oriented Ga-containingsubstrate. The apparatus can include a laser driver module coupled tothe laser source. The apparatus can include a digital light processing(DLP) chip comprising a digital mirror device. The digital mirror deviceincludes a plurality of mirrors, each of the mirrors corresponding topixels of the frames of images. The apparatus includes a power sourceelectrically coupled to the laser source and the digital lightprocessing chip.

The apparatus can include a laser driver module coupled to the lasersource. The apparatus includes an optical member provided withinproximity of the laser source, the optical member being adapted todirect the laser beam to the digital light processing chip. Theapparatus includes a power source electrically coupled to the lasersource and the digital light processing chip. In one embodiment, thedynamic properties of the light source may be initiated by the user ofthe apparatus. For example, the user may activate a switch, dial,joystick, or trigger to modify the light output from a static to adynamic mode, from one dynamic mode to a different dynamic mode, or fromone static mode to a different static mode.

In an alternative embodiment, a liquid crystal on silicon (LCOS)micro-display chip is included in the device and is configured to steer,pattern, and/or pixelate a beam of light by reflecting or absorbing thelight from a 2-dimensional array of liquid crystal mirrors correspondingto pixels at a predetermined angle to turn each pixel on or off. In oneexample, the LCOS chip is configured to steer a collimated beam of laserexcitation light from the one or more laser diodes to generate apredetermined spatial and/or temporal pattern of excitation light on thewavelength conversion or phosphor member. At least a portion of thewavelength converted light from the phosphor member could then berecollimated or shaped using a beam shaping element such as an optic. Inthis example the micro-display is upstream of the wavelength convertermember in the optical pathway. In a second example the LCOSmicro-display chip is configured to steer a collimated beam of at leasta partially wavelength converted light to generate a predeterminedspatial and/or temporal pattern of converted light onto a target surfaceor into a target space. In this example the micro-display is downstreamof the wavelength converter member in the optical pathway. The formerexample is the preferred example since LCOS chips are polarizationsensitive and the output of laser diodes is often highly polarized, forexample greater than 70%, 80%, 90%, or greater than 95% polarized. Thishigh polarization ratio of the direct emission from the laser sourceenables high optical throughput efficiencies for the laser excitationlight compared to LEDs or legacy light sources that are unpolarized,which wastes about half of the light.

LCOS micro-display chips are configured spatial light modulation whereinthe image is created by tiny active elements laid out in an array on asilicon chip. The elements reflectivity is modulated at rapid rates toselectively reflect light through an optical beam shaping element suchas a lens. The number of elements corresponds or correlates to theresolution of the projected image. Common resolutions for such LCOSmicro-display chips include 800×600, 1024×768, 1280×720, and 1920×1080(HDTV), and even greater.

Optionally, the partially converted light emitted from the wavelengthconversion element results in a color point, which is white inappearance. Optionally, the color point of the white light is located onthe Planckian blackbody locus of points. Optionally, the color point ofthe white light is located within du‘v’ of less than 0.010 of thePlanckian blackbody locus of points. Optionally, the color point of thewhite light is preferably located within du‘v’ of less than 0.03 of thePlanckian blackbody locus of points. Optionally, the pump light sourcesare operated independently, with their relative intensities varied todynamically alter the color point and color rendering index (CRI) of thewhite light.

In several preferred embodiments one or more beam shaping elements areincluded in the present invention. Such beam shaping elements could beincluded to configure the one or more laser diode excitation beams inthe optical pathway prior to incidence on the phosphor or wavelengthconversion member. In some embodiments the beam shaping elements areincluded in the optical pathway after at least a portion of the laserdiode excitation light is converted by the phosphor or wavelengthconversion member. In additional embodiments the beam shaping elementsare included in the optical pathway of the non-converted laser diodelight. Of course, in many preferred embodiments, a combination of one ormore of each of the beam shaping elements is included in the presentinvention.

In some embodiments, a laser diode output beam must be configured to beincident on the phosphor material to excite the phosphor. In someembodiments, the laser beam may be directly incident on the phosphor andin other embodiments the laser beam may interact with an optic,reflector, or other object to manipulate or shape the beam prior toincidence on the phosphor. Examples of such optics include, but are notlimited to ball lenses, aspheric collimator, aspheric lens, fast or slowaxis collimators, dichroic mirrors, turning mirrors, optical isolators,but could be others. In some embodiments, other optics can be includedin various combinations for the shaping, collimating, directing,filtering, or manipulating of the optical beam. Examples of such opticsinclude, but are not limited to re-imaging reflectors, ball lenses,aspheric collimator, dichroic mirrors, turning mirrors, opticalisolators, but could be others.

In some embodiments, the converted light such as a white light source iscombined with one or more optical members to manipulate the generatedwhite light. In an example the converted light source such as the whitelight source could serve in a spot light system such as a flashlight,spotlight, automobile headlamp or any direction light applications wherethe light must be directed or projected to a specified location or area.In one embodiment a reflector is coupled to the white light source.Specifically, a parabolic (or paraboloid or paraboloidal) reflector isdeployed to project the white light. By positioning the white lightsource in the focus of a parabolic reflector, the plane waves will bereflected and propagate as a collimated beam along the axis of theparabolic reflector. In another example a lens is used to collimate thewhite light into a projected beam. In one example a simple aspheric lenswould be positioned in front of the phosphor to collimate the whitelight. In another example, a total internal reflector optic is used forcollimation. In other embodiments other types of collimating optics maybe used such as spherical lenses or aspherical lenses. In severalembodiments, a combination of optics is used.

In some embodiments, the smart white light source containing at least alaser-based light module includes a beam shaping element. Optionally,the beam shaping element provides an optical beam where greater than 80%of the emitted light is contained within an emission angle of 30degrees. Optionally, the beam shaping element provides an optical beamwhere greater than 80% of the emitted light is preferably containedwithin an emission angle of 10 degrees. Optionally, the beam shapingelement provides an optical beam where greater than 80% of the emittedlight is preferably contained within an emission angle of 5 degrees. Insome embodiments collimating optics are used such as parabolicreflectors, total internal reflector (UR) optics, diffractive optics,other types of optics, and combinations of optics.

Optionally, the smart white light source can be formed within thecommonly accepted standard shape and size of existing MR, PAR, and AR111lamps. Optionally, the solid-state white light source further containsan integrated electronic power supply to electrically energize thelaser-based light module. Optionally, the solid-state white light sourcefurther contains an integrated electronic power supply with input powerwithin the commonly accepted standards. Of course, there can be othervariations, modifications, and alternatives.

In an embodiment, a laser or SLED driver module is provided. Forexample, the laser driver module generates a drive current, with thedrive currents being adapted to drive a laser diode to transmit one ormore signals such as digitally encoded frames of images, digital oranalog encodings of audio and video recordings or any sequences ofbinary values. In a specific embodiment, the laser driver module isconfigured to generate pulse-modulated signals at a frequency range ofabout 50 to 300 MHz, 300 MHz to 1 GHz or 1 GHz to 100 GHz. In anotherembodiment the laser driver module is configured to generate multiple,independent pulse-modulated signal at a frequency range of about 50 to300 MHz, 200 MHz to 1 GHz or 1 GHz to 100 GHz. In an embodiment, thelaser driver signal can be modulated by a low-power analog voltage orcurrent signal.

In an embodiment, the apparatus is capable of conveying information tothe user or another observer through the means of dynamically adjustingcertain qualities of the projected light. Such qualities include spotsize, shape, hue, and color-point as well as through independent motionof the spot. As an example the apparatus may convey information bydynamically changing the shape of the spot. In an example, the apparatusis used as a flash-light or bicycle light, and while illuminating thepath in front of the user it may convey directions or informationreceived from a paired smart phone application. Changes in the shape ofthe spot which could convey information include, among others: formingthe spot into the shape of an arrow that indicates which direction theuser should walk along to follow a predetermined path and forming thespot into an icon to indicate the receipt of an email, text message,phone call or other push notification. The white light spot may also beused to convey information by rendering text in the spot. For example,text messages received by the user may be displayed in the spot. Asanother example, embodiments of the apparatus including mechanisms foraltering the hue or color point of the emitted light spectrum couldconvey information to the user via a change in these qualities. Forexample, the aforementioned bike light providing directions to the usermight change the hue of the emitted light spectrum from white to redrapidly to signal that the user is nearing an intersection or stop-signthat is beyond the range of the lamp.

In an embodiment, a modem circuit is provided. The modem circuit encodesbinary data into a control signal that is routed to the pump lightdriver.

In an embodiment, the apparatus is capable of conveying information tothe user or another observer both through the means of dynamicallyadjusting certain qualities of the projected light. Such qualitiesinclude spot size, shape, hue, and color-point as well as throughindependent motion of the spot as well as via visible lightcommunication or LiFi. In an example use, the apparatus might be used asa bike-light which conveys information about directions to the user fortravelling along a predetermined path by dynamically adjusting the shapeor color of the emitted light spot. The apparatus may then also conveyinformation about the user to objects illuminated by the spot using VLCor LiFi. Such data may be used by autonomous vehicles to better predictthe actions or path of the user.

In a second group of embodiments, the present invention covers dynamicgallium and nitrogen based laser light sources coupled to one or moresensors with a feedback loop or control circuit to trigger the lightsource to react with one or more predetermined responses such as a lightmovement response, a light color response, a light brightness response,a spatial light pattern response, a communication response, or otherresponses.

In a specific embodiment of the present invention including a dynamiclight source, the dynamic feature is activated by a feedback loopincluding a sensor. Such sensors may be selected from, but not limitedto a microphone, geophone, hydrophone, a chemical sensor such as ahydrogen sensor, CO₂ sensor, or electronic nose sensor, flow sensor,water meter, gas meter, Geiger counter, altimeter, airspeed sensor,speed sensor, range finder, piezoelectric sensor, gyroscope, inertialsensor, accelerometer, MEMS sensor, Hall effect sensor, metal detector,voltage detector, photoelectric sensor, photodetector, photoresistor,pressure sensor, strain gauge, thermistor, thermocouple, pyrometer,temperature gauge, motion detector, passive infrared sensor, Dopplersensor, biosensor, capacitance sensor, video sensor, transducer, imagesensor, infrared sensor, radar, SONAR, LIDAR, or others.

In one example, a dynamic light feature including a feedback loop with asensor a motion sensor is included. The dynamic light source isconfigured to illuminate a location where the motion is detected bysensing the spatial of position of the motion and steering the outputbeam to that location. In another example of a dynamic light featureincluding a feedback loop with a sensor an accelerometer is included.The accelerometer is configured to anticipate where the laser lightsource apparatus is moving toward and steer the output beam to thatlocation even before the user of the apparatus can move the light sourceto be pointing at the desired location. Of course, these are merelyexamples of implementations of dynamic light sources with feedback loopsincluding sensors. There can be many other implementations of thisinvention concept that includes combining dynamic light sources withsensors.

In some embodiments, the invention may be applicable as a visible lightcommunication transceiver for bi-directional communication. Optionally,the light engine also contains a photodiode, avalanche photodiode,photomultiplier tube or other means of converting a light signal toelectrical energy. The detector is connected to the modem. In thisembodiment the modem is also capable of decoding detected light signalsinto binary data and relaying that data to a control system such as acomputer, cell-phone, wrist-watch, or other electronic device.

In some embodiments, the present invention provides a smart whitelight-source to be used on automotive vehicles for illumination of theexterior environment of the vehicle. An exemplary usage would be as aparking light, headlight, fog-light, signal-light or spot-light. In anembodiment, a lighting apparatus is provided including a housing havingan aperture. Additionally, the lighting apparatus includes one or morepump light sources including one or more blue lasers or blue SLEDsources. The individual blue lasers or SLEDS have an emission spectrumwith center wavelength within the range 400 to 480 nm. The one or moreof the pump light sources emitting in the blue range of wavelengthsilluminates a wavelength converting element which absorbs part of thepump light and reemits a broader spectrum of longer wavelength light.Each pump light source is configured such that both light from thewavelength converting element and light directly emitted from the one ormore light sources being combined as a white light spectrum. Thelighting apparatus further includes optical elements for focusing andcollimating the white light and shaping the white light spot.

In this smart lighting apparatus, each pump light source isindependently addressable, and is controlled by a laser driver moduleconfigured to generate pulse-modulated signal at a frequency range ofbetween 10 MHz and 100 GHz. The laser driver includes an input interfacefor receiving digital or analog signals from sensors and electroniccontrollers in order to control the modulation of the pump laser sourcesfor the transmission of data. The lighting apparatus can transmit dataabout the vehicle or fixture to which it is attached via the modulationof the blue or violet lasers or SLED sources to other vehicles whichhave appropriately configured VLC receivers. For example, the whitelight source could illuminate oncoming vehicles. Optionally, it couldilluminate from behind or sides vehicles travelling in the samedirection. As an example the lighting apparatus could illuminateVLC-receiver enabled road signs, road markings, and traffic signals, aswell as dedicated VLC receivers installed on or near the highway. Thelighting apparatus would then broadcast information to the receivingvehicles and infrastructure about the broadcasting vehicle. Optionally,the lighting apparatus could transmit information on the vehicle'slocation, speed and heading as well as, in the case of autonomous orsemiautonomous vehicles, information about the vehicle's destination orroute for purposes of efficiently scheduling signal light changes orcoordinating cooperative behavior, such as convoying, between autonomousvehicles.

In some embodiments, the present invention provides a communicationdevice which can be intuitively aimed. An example use of thecommunication device would be for creation of temporary networks withhigh bandwidth in remote areas such as across a canyon, in a ravine,between mountain peaks, between buildings separated by a large distanceand under water. In these locations, distances may be too large for astandard wireless network or, as in the case of being under water, radiofrequency communications may be challenging due to the absorption ofradio waves by water. The communication device includes a housing havingan aperture. Additionally, the communication device includes one or moreblue laser or blue SLED source. The individual blue lasers or SLEDS havean emission spectrum with center wavelength within the range 400 nm to480 nm. One or more of the light sources emitting in the blue range ofwavelengths illuminates a wavelength converting element which absorbspart of the pump light and reemits a broader spectrum of longerwavelength light. The light source is configured such that both lightfrom the wavelength converting element and the plurality of lightsources are emitted as a white light spectrum. The communication deviceincludes optical elements for focusing and collimating the white lightand shaping the white light spot. Optionally, each light source in thecommunication device is independently addressable, and is controlled bya driver module configured to generate pulse-modulated signal at afrequency range of between 10 MHz and 100 GHz. The driver moduleincludes an input interface for receiving digital or analog signals fromsensors and electronic controllers in order to control the modulation ofthe laser sources for the transmission of data.

The communication device includes one or more optical detectors to actas VLC-receivers and one or more band-pass filters for differentiatingbetween two or more of the laser or SLED sources. Optionally, aVLC-receiver may detect VLC signals using multiple avalanche photodiodescapable of measuring pulse-modulated light signals at a frequency rangeof about 50 to 300 MHz. Optionally, the communication device containsone or more optical elements, such as mirrors or lenses to focus andcollimate the light into a beam with a divergence of less than 5 degreesin a less preferred case and less than 2 degrees in a most preferredcase. Two such apparatuses would yield a spot size of between roughly 3and 10 meters in diameter at a distance of 100 to 300 meters,respectively, and the focused white light spot would enable operators toaim the VLC-transceivers at each other even over long distances simplyby illuminating their counterpart as if with a search light.

In some embodiments, the communication device disclosed in the presentinvention can be applied as flash sources such as camera flashes thatcarrying data information. Data could be transmitted through the flashto convey information about the image taken. For example, an individualmay take a picture in a venue using a camera phone configured with aVLC-enabled solid-state light-source in accordance with an embodiment ofthis invention. The phone transmits a reference number to VLC-receiversinstalled in the bar, with the reference number providing a method foridentifying images on social media websites taken at a particular timeand venue.

In some embodiments, the present invention provides a projectionapparatus. The projection apparatus includes a housing having anaperture. The apparatus also includes an input interface for receivingone or more frames of images. The apparatus includes a video processingmodule. Additionally, the apparatus includes one or more blue laser orblue SLED sources disposed in the housing. The individual blue lasers orSLEDs have an emission spectrum with center wavelength within the range400 nm to 480 nm. One or more of the light sources emitting in the bluerange of wavelengths illuminates a wavelength converting element whichabsorbs part of the pump light and reemits a broader spectrum of longerwavelength light. The light source is configured such that both lightfrom the wavelength converting element and the plurality of lightsources are emitted as a white light spectrum. Additionally, theapparatus includes optical elements for focusing and collimating thewhite light and shaping the white light spot. In this apparatus, eachlight source is independently addressable, and is controlled by a laserdriver module configured to generate pulse-modulated signal at afrequency range of between 10 MHz and 100 GHz. The laser driver alsoincludes an input interface for receiving digital or analog signals fromsensors and electronic controllers in order to control the modulation ofthe laser sources for the transmission of data. Furthermore, theapparatus includes a power source electrically coupled to the lasersource and the digital light processing chip. Many variations of thisembodiment could exist, such as an embodiment where the green and bluelaser diode share the same substrate or two or more of the differentcolor lasers could be housed in the same packaged. The outputs from theblue, green, and red laser diodes would be combined into a single beam.

In an embodiment, the present invention provides a lighting apparatusenabling visible light communication with various appliances, electronicdevices and sensors within an area illuminated by artificial lightingsuch as in a home, office building, factory, store or shop, warehouse,parking deck, theater, grocery store, parking lot, and street or roadamong other places. The apparatus includes a housing holding one or moreblue laser sources or blue SLED sources and having an aperture. Theindividual blue lasers or SLEDs have an emission spectrum with centerwavelength within the range 400 nm to 480 nm. One or more of the bluelight sources emitting in the range of blue light wavelengthsilluminates a wavelength converting element which absorbs part of theblue light and reemits a broader spectrum of longer wavelength light.The apparatus is configured such that both light from the wavelengthconverting element and the plurality of light sources are emitted as awhite light spectrum. The apparatus may include optical elements forfocusing and collimating the white light and shaping the white lightspot. In this apparatus, one or more of the blue laser devices isindependently addressable, and is controlled by a laser driver moduleconfigured to generate a modulated current at a frequency range ofbetween 10 MHz and 100 GHz. The laser driver also includes an inputinterface for receiving digital or analog signals. For example, theapparatus may be provided with a FM or AM radio receiver, a short-rangeradio frequency transceiver for communication over a wireless local areanetwork or personal area network. For example, the apparatus may beprovided with a receiver or transceiver for communication using the IEEE802.11 communication standard, the Bluetooth communication protocol, orsimilar radio frequency bases communication standard. In anotherexample, the apparatus is provided with a receiver or transceiverenabling communication over power lines providing electrical power tothe apparatus. In an example, the apparatus is provided with a receiverfor visible light communication, making the apparatus a VLC-transceiver.In an example, the apparatus is provided with a receiver or transceiverfor a wired local area network protocol such as Ethernet or fiber opticcommunication among others. The apparatus receives data from theprovided RF, wired or VLC-based communication channel and retransmitsthe data via the modulation of the blue lasers or SLED sources.

Merely by way of example, such an apparatus would be advantageous intransmitting data to distributed sensors and appliances. For example, aprinter could be positioned anywhere in a room without regard toreception of wireless networks or access to wired networks. A request toprint a document along with the data describing the document could thenbe sent to the printer regardless of the printer's location within thebuilding so long as the printer is illuminated by the apparatus. Otherappliances which could be communicated to include: televisions,refrigerators, toaster ovens, ovens, dishwashers, clothes washers anddriers, thermostats, microwave ovens, smoke detectors, fire detectors,carbon monoxide detectors, humidifiers, light sources, emergency exitsigns and emergency lighting fixtures among others. In the case of suchan apparatus provided with an Ethernet or fiberoptic based transceiver,the apparatus could provide wireless transmission over VLC protocols toa plurality of electronic devices at transfer rates much higher thanthose achievable with a WiFi based technology.

FIG. 33A is a functional block diagram for a dynamic light sourceaccording to some embodiments of the present invention. This diagram ismerely an example, which should not unduly limit the scope of theclaims. One of ordinary skill in the art would recognize manyvariations, alternatives, and modifications. As shown, the dynamic lightsource includes one or more violet or blue laser devices 1704, 1705,1706 and 1707. Each individual violet or blue laser device emits aspectrum with a center wavelength in the range of 380-480 nm.Optionally, the dynamic light source includes one or more beam shapingoptical elements 1708, 1709, 1710 and 1711. The laser devices 1704,1705, 1706 and 1707 are configured such that their emitting facets areaimed at the one or more beam shaping optical elements 1708, 1709, 1710and 1711, respectively for collimating, focusing or otherwise shapingthe beams emitted by the one or more blue laser devices. The beamshaping optical elements may be comprised of lenses or mirrors, andprovide functions such as beam collimation and focusing as well ascontrol of the propagation direction of the laser light. The laser lightfrom each blue laser device is incident on a wavelength convertingelement 1713. The beam steering optical element 1712 directs the laserlight onto a wavelength converting element 1713. The position of thelaser light on the wavelength converting element 1713 is dynamicallycontrolled by a beam steering optical element 1712 which is controlledby a steering element driver 1714. Optionally, the beam steering opticalelement 1712 can one or a combination of many of a mirror galvanometer,a MEMs scanning mirror, a rotating polygon mirror, a DLP chip, an LCOSchip, a fiber scanner, or the like. The steering element driver 1714 isconfigured to take input from an external system such as amicrocontroller or analog circuit to control the positioning of the beamsteering optical element 1712 so as to dynamically control how laserlight illuminates the wavelength converting element 1713 such that awhite light spot with dynamically controllable shape and intensityprofile can be formed on the wavelength converting element 1713.

Fiber scanner has certain performance advantages and disadvantages overscanning mirror as the beam steering optical element in the dynamiclight source. Scanning mirror appears to have significantly moreadvantages for display and imaging applications. For example, thescanning frequency can be achieved much higher for scanning mirror thanfor fiber scanner. Mirror scanner may raster at near 1000 kHz withhigher resolution (<1 μm) but without 2D scanning limitation while fiberscanner may only scan at up to 50 kHz with 2D scanning limitation.Additionally, mirror seamier can handle much higher light intensity thanfiber seamier. Mirror scanner is easier to be physically set up withlight optimization for white light or RGB light and incorporated withphotodetector for image, and is less sensitive to shock and vibrationthan fiber scanner. Since light beam itself is directly scanned inmirror scanner, no collimation loss, AR loss, and turns limitationexist, unlike the fiber itself is scanned in fiber scanner which carriescertain collimation loss and AR loss over curved surfaces. Of course,fiber scanner indeed is advantageous in providing much larger angulardisplacement (near 80 degrees) over that (about +/−20 degrees) providedby mirror scanner.

A VLC modem 1701 is provided in the dynamic light source. The VLC modem1701 is capable of receiving digital control data from a data source viaa wired or wireless link to provide control signal for a laser driver1702. The laser driver 1702 supplies controlled current at a controlledvoltage to the one or more laser devices 1704, 1705, 1706 and 1707.Optionally, the laser driver 1702 can individually control/modulate theone or more of the violet or blue laser devices 1704, 1705, 1706 and1707.

Optionally, one or more optical elements are provided for imaging thecombined light of each blue laser device and the light emitted by thewavelength converting element 1713 onto a projection surface. Oneoptical element for projecting image includes a color wheel. As anexample, the color wheel may include phosphor material that modifies thecolor of light emitted from the light source. Optionally, the colorwheel includes multiple regions, each of the regions corresponding to aspecific color (e.g., red, green, blue, etc.). Optionally, the colorwheel includes a slot or transparent section for the blue color lightand a phosphor containing region for converting blue light to greenlight. In operation, the blue light source (e.g., blue laser diode orblue LED) provides blue light through the slot and excites green lightfrom the phosphor containing region; the red light source provides redlight separately. The green light from the phosphor may be transmittedthrough the color wheel, or reflected back from it. In either case thegreen light is collected by optics and redirected to the microdisplay.The blue light passed through the slot is also directed to themicrodisplay. The blue light source may be a laser diode or LEDfabricated on non-polar or semi-polar oriented GaN. Alternatively, agreen laser diode may be used, instead of a blue laser diode withphosphor, to emit green light. It is to be appreciated that can be othercombinations of colored light sources and color wheels thereof.

FIG. 33B is a diagram of a dynamic light source with beam steeringelement according to an example of some embodiments of FIG. 33A of thepresent invention. This diagram is merely an example, which should notunduly limit the scope of the claims. One of ordinary skill in the artwould recognize many variations, alternatives, and modifications. Asshown, the light source is an laser-based smart light source assembledin a case 1700. The laser diode 1724 is one of violet or blue laserdevices according to the invention. Laser light firstly passes through acollimation lens 1725 and is split by a beamsplitter 1726. One portionof laser light is directed to a photodetector 1727 for intensitymonitoring. Another portion of laser light is further guided to a mirror1728 which re-directs the light to a beam steering/scanning device 1722which can be controlled by a servo controller to dynamically change thebeam direction based on certain feedback signals. The laser light comingout of the beam steering/scanning device 1722 firstly passes through are-imaging lens 1734 for focusing the beam to a light converting element1735 to convert the violet or blue laser to white light, then is guidedout of a window 1736 of the case 1700. Optionally, the beamsteering/scanning device 1722 is made of a plurality of MEMS scanningmirrors. Optionally, the beam steering/scanning device 1722 is arotating polygonal mirror, LCOS, DLP, or the like. Optionally, the lightconverting element 1735 is a phosphor material.

This white light or multi-colored dynamic image projection technologyaccording to this invention enables smart lighting benefits to the usersor observers. This embodiment of the present invention is configured forthe laser-based light source to communicate with users, items, orobjects in two different methods wherein the first is through VLCtechnology such as LiFi that uses high-speed analog or digitalmodulation of a electromagnetic carrier wave within the system, and thesecond is by the dynamic spatial patterning of the light to createvisual signage and messages for the viewers to see. These two methods ofdata communication can be used separately to perform two distinctcommunication functions such as in a coffee shop or office setting wherethe VLC/LiFi function provides data to users' smart phones and computersto assist in their work or internet exploration while the projectedsignage or dynamic light function communicates information such asmenus, lists, directions, or preferential lighting to inform, assist, orenhance users experience in their venue.

This white light or multi-colored dynamic image projection technologyaccording to this invention enables smart lighting benefits to the usersor observers. This embodiment of the present invention is configured forthe laser-based light source to communicate with users, items, orobjects in two different methods wherein the first is through VLCtechnology such as LiFi that uses high-speed analog or digitalmodulation of a electromagnetic carrier wave within the system, and thesecond is by the dynamic spatial patterning of the light to createvisual signage and messages for the viewers to see. These two methods ofdata communication can be used separately to perform two distinctcommunication functions such as in a coffee shop or office setting wherethe VLC/LiFi function provides data to users' smart phones and computersto assist in their work or internet exploration while the projectedsignage or dynamic light function communicates information such asmenus, lists, directions, or preferential lighting to inform, assist, orenhance users experience in their venue.

FIG. 34A is a schematic diagram of a scanned phosphor display withreflection architecture according to an embodiment of the presentinvention. This diagram is merely an example, which should not undulylimit the scope of the claims. One of ordinary skill in the art wouldrecognize many variations, alternatives, and modifications. As shown, acontroller is Configured to receive video data and convert the data toreal-time driving signals for the laser devices (in violet or bluewavelength ranges) to produce laser beams based on the driving signals.The laser beams are passing through a collimation lens before hitting aMEMS scanner. The MEMS scanner is controlled by a servo control unitwhich is also controlled by the controller. The MEMS scanner isconfigured to controllably guide the laser beams to respective spots ofa dichronic mirror which reflects the laser beams to a phosphormaterial. The MEMS scanner is dynamically changing the laser spotpositions based on the received video signal. The phosphor material actsas a light converting material to convert the violet or blue laser towhite light. The phosphor material is set up as a reflective film toguide the white light back passing through the dichroic mirror. Are-imaging lens is inserted between the dichronic mirror and a screenwhich displays a patterned image dynamically controlled by the MEMSscanner.

FIG. 34B is a schematic diagram of a scanned phosphor display withtransmission architecture according to an embodiment of the presentinvention. This diagram is merely an example, which should not undulylimit the scope of the claims. One of ordinary skill in the art wouldrecognize many variations, alternatives, and modifications. As shown,this scanned phosphor display is substantially similar to that shown inFIG. 34A. Optionally, the phosphor material is set up as a transmissionfilm to allow the incoming laser light to pass through and convert towhite light.

FIG. 34C is a schematic diagram of a scanned phosphor display withreflection architecture according to an alternative embodiment of thepresent invention. This diagram is merely an example, which should notunduly limit the scope of the claims. One of ordinary skill in the artwould recognize many variations, alternatives, and modifications. Asshown, this scanned phosphor display is another alternative variation ofthat shown in FIG. 34A. Optionally, the dichronic mirror is configuredto allow the blue light first passing through to reach the phosphormaterial. The phosphor material is configured to be in reflection modeto reflect the white light generated by converting the incoming bluelight. The white light beam is then reflected by the dichronic mirrorand guided toward, passing a re-imaging lens, the screen orphotodetectors. Note, the white light spots are displayed directly onscreen or detected by the photodetectors, and no visible lightcommunication is required for this scanned phosphor display.

According to an embodiment, the present invention provides a dynamiclight source or “light-engine” that can function as a white light sourcefor general lighting applications with tunable colors. The light-engineconsists of three or more laser or SLED light sources. At least onelight source emits a spectrum with a center wavelength in the range of380-480 nm and acts as a blue light source. At least one light emits aspectrum with a center wavelength in the range of 480-550 nm and acts asa green light source. At least one light emits a spectrum with a centerwavelength in the range 600-670 nm and acts as a red light source. Eachlight source is individually addressable, such that they may be operatedindependently of one another and act as independent communicationchannels, or in the case of multiple emitters in the red, green or bluewavelength ranges the plurality of light sources in each range may beaddressed collectively, though the plurality of sources in each rangeare addressable independently of the sources in the other wavelengthranges. One or more of the light sources emitting in the blue range ofwavelengths illuminates a wavelength converting element which absorbspart of the pump light and reemits a broader spectrum of longerwavelength light. The light engine is configured such that both lightfrom the wavelength converting element and the plurality of lightsources are emitted from the light-engine. A laser or SLED driver moduleis provided which can dynamically control the light engine based oninput from an external source. For example, the laser driver modulegenerates a drive current, with the drive currents being adapted todrive one or more laser diodes, based on one or more signals.

FIG. 35 is a schematic representation of a use case for an apparatus inaccordance with an embodiment of this invention. The apparatus 2602 isused to project an image 2603 containing information in the form oftext, pictograms, moving shapes, variation in hue and the like. Encodedin the projected light using VLC encoding schemes is a data stream 2604.The data stream can be received by multiple smart devices carried orworn by the user to provide more information to the user. For example,the digital data stream may provide more detailed information about arestaurant's menu or may provide the address to a website containingmore information. In this case, the user receives the VLC data using awearable device such as smart glasses 2609 as well as a smart phone2608, though it should be obvious to one skilled in the art that otherdevices may receive and process this data. For example, one couldreceive and process data using smart watches, virtual and augmentedreality head-sets, tablet computers and laptop computers among others.Data can be provided to the apparatus either as a digital informationprovided through RF transmission, WiFi, LiFi or VLC, or via transmissionalong wires. The apparatus may use VLC to transmit data that is storedin the apparatus and not received from an external source. In this case,the data may be stored in volatile or non-volatile memory formats aseither an integrated part of the apparatus or in a removable format suchas a card, hard-disk, compact disk read only memory [CD-ROM] or anyother optical or magnetic storage medium.

In another aspect, the present invention provides a dynamic light sourceor “light-engine” that can function as a white light source for generallighting applications with tunable colors.

In an embodiment, the light-engine consists of two or more lasers orSLED light sources. At least one of the light sources emits a spectrumwith a center wavelength in the range of 380-450 run. At least one ofthe light sources emits a spectrum with a center wavelength in the rangeof 450-520 nm. This embodiment is advantageous in that for manyphosphors in order to achieve a particular color point, there will be asignificant gap between the wavelength of the laser light source and theshortest wavelength of the spectrum emitted by the phosphor. Byincluding multiple blue lasers of significantly different wavelengths,this gap can be filled, resulting in a similar color point with improvedcolor rendering.

In an embodiment, the green and red laser light beams are incident onthe wavelength converting element in a transmission mode and arescattered by the wavelength converting element. In this embodiment thered and green laser light is not strongly absorbed by the wavelengthconverting element.

In and embodiment, the wavelength converting element consists of aplurality of regions comprised of varying composition or colorconversion properties. For example, the wavelength converting elementmay be comprised by a plurality of regions of alternating compositionsof phosphor. One composition absorbs blue or violet laser light in therange of wavelengths of 385 to 470 nm and converts it to a longerwavelength of blue light in the wavelength range of 430 nm to 480 nm. Asecond composition absorbs blue or violet laser light and converts it togreen light in the range of wavelengths of 480-550 nm. A thirdcomposition absorbs blue or violet laser light and converts it to redlight in the range of wavelengths of 550 to 670 nm. Between the laserlight source and the wavelength converting element is a beam steeringmechanism such as a MEMS mirror, rotating polygonal mirror, mirrorgalvanometer, or the like. The beam steering element scans a violet orblue laser spot across the array of regions on the wavelength convertingelement and the intensity of the laser is synced to the position of thespot on the wavelength converting element such that red, green and bluelight emitted or scattered by the wavelength converting element can bevaried across the area of the wavelength converting element.

In an embodiment, the phosphor elements are single crystal phosphorplatelets.

In an embodiment, the phosphor elements are regions of phosphor powdersintered into platelets or encapsulated by a polymer or glassy binder.

In another embodiment, the plurality of wavelength converting regionscomprising the wavelength converting element are composed of an array ofsemiconductor elements such as InGaN, GaN single or multi-quantum wellsfor the production of blue or green light and single andmulti-quantum-well structures composed of various compositions ofAlInGaAsP for production of yellow and red light, although this ismerely an example, which should not unduly limit the scope of theclaims. One of ordinary skill in the art would recognize otheralternative semiconductor materials or light-converting structures.

In another embodiment, the plurality of wavelength converting regionscomprising the wavelength converting element are composed of an array ofsemiconductor elements such as InGaN GaN quantum dots for the productionof blue, red or green light and quantum dots composed of variouscompositions of AlInGaAsP for production of yellow and red light,although this is merely an example, which should not unduly limit thescope of the claims. One of ordinary skill in the art would recognizeother alternative semiconductor materials or light-convertingstructures.

FIG. 36A is a schematic representation of a wavelength convertingelement consisting of a plurality of wavelength converting regions inaccordance with an embodiment. The plurality of wavelength convertingregions are comprised of regions 1902 that converts blue or violet laserlight to a predominantly red spectrum, regions 1903 that converts blueor violet laser light to a predominantly green spectrum, and regions1904 that converts violet laser light into a predominantly blue spectrumor blue laser light into a spectrum predominantly of a longer wavelengthof blue light than the blue laser. The plurality of wavelengthconverting regions are surrounded by a matrix 1901 which can be either apolymer, metal, ceramic, glass or composite material. To one skilled inthe art, it should be obvious that there are many configurations for theshape and relative positions of the regions 1902, 1903, and 1904. Ingeneral, the lateral dimensions should be at a minimum the same as thespot size of the blue or violet pump laser when projected onto thewavelength converting region.

In another embodiment, the wavelength converting element also containsregions of non-wavelength converting material that scatters the laserlight. The advantage of this configuration is that the blue laser lightis diffusely scattered without conversion losses, thereby improving theefficiency of the overall light source. Examples of such non-convertingbut scattering materials are: granules of wide-bandgap ceramics ordielectric materials suspended in a polymer or glassy matrix,wide-bandgap ceramics or dielectric materials with a roughened surface,a dichroic mirror coating overlaid on a roughened or patterned surface,or a metallic mirror or metallic-dielectric hybrid mirror deposited on arough surface.

FIG. 36B is a schematic representation of the cross-section AA from FIG.36A in accordance with an embodiment. The cross section shows aplurality of wavelength converting or scattering regions 1902, 1903 and1904 embedded in a matrix 1901 that provides physical support as well asa path for conduction of heat away from the regions. The matrixsurrounds the edges of the regions 1902, 1903, and 1904 as well as theback of the regions. A bonding layer 1905 is provided. The bonding layercan be composed of polymers such as epoxies or glues or one or moremetals such as gold, copper, aluminum, silver, gold-tin solder or othersolders, eutectic solders, and the like.

FIG. 36C is a schematic representation of the cross-section AA from FIG.36A in accordance with another embodiment. The cross section shows aplurality of wavelength converting or scattering regions 1902, 1903 and1904 embedded in a matrix 1901 that provides physical support as well asa path for conduction of heat away from the regions. The matrixsurrounds the edges of the regions 1902, 1903, and 1904 but does notoverlay the backsides of the regions. A bonding layer 1905 is provided.The bonding layer can be composed of polymers such as epoxies or gluesor one or more metals such as gold, copper, aluminum, silver, gold-tinsolder or other solders, eutectic solders, and the like. Thisconfiguration is advantageous when the matrix material is not highlythermally conductive. By contacting the wavelength converting regionsdirectly with a highly thermally conductive bonding layer, a highlythermally conductive path can be formed to a heat-sink in order toefficiently remove heat from the wavelength converting elements.

In some embodiments, the apparatus dynamically adjusts the spatialvariation of the white light spot or spatially varies the brightness ofarea within the spot based on pre-programmed responses to various inputsor on control by a smart device.

In an example embodiment, the apparatus may adjust the shape of thewhite light spot as well as spatially vary the brightness of the spot inresponse to the time of day. The dynamic control of the spot may bepreprogrammed into the apparatus. As an example, the apparatus may beprogrammed to adjust the emitted white light to form a wide spot ofmaximum uniform brightness during mid-morning to afternoon hours. Theapparatus may be programmed to progressively narrow the dimensions ofthe spot and reduce the brightness across the late afternoon such thatby night-time, the spot is at a minimum diameter and brightness suchthat the room in which the apparatus is located is ascetically lit forthe nighttime.

Such an apparatus could also have preprogrammed responses to otherinputs such as room temperature, ambient lighting from windows or otherlight sources, day of the year or week, among others.

In another example embodiment, the apparatus is paired with a smartdevice through which commands can be given to the apparatus to controlthe shape of and spatial variation of brightness within illuminated areaof the light. In this context, smart devices include tablet computers,laptop and desktop computers, smart watches and smart phones which arecapable of executing arbitrary software applications, among others.Commands from the smart-device may include continuous adjustment of theoutput of the apparatus by the user, or predetermined configurations ofspot shape, size and brightness variation.

The smart-device may also be able to command the apparatus to adopt morethan one configuration in a sequence in order to convey some informationto a user. As an example, the smart-device may command the apparatus torepeatedly narrow and then enlarge the spot size at some fixed cadencein order to signal the arrival of a telephone call. Other changes oflight spot configuration as well as other triggers causing a command tobe sent to the apparatus from the smart device are possible.

FIG. 37A is a functional block diagram for a laser-based smart-lightingsystem according to some embodiments of the present invention. Thisdiagram is merely an example, which should not unduly limit the scope ofthe claims. One of ordinary skill in the art would recognize manyvariations, alternatives, and modifications. As shown, thesmarting-lighting system includes a laser-based dynamic white lightsource including a blue laser device 2005 emitting a spectrum with acenter wavelength in the range of 380-480 nm. The system includes anoptional beam shaping optical element 2006 provided for collimating,focusing or otherwise shaping the beam emitted by the laser device 2005.The laser light from the laser device 2005 is incident on a wavelengthconverting element 2007. The system additionally includes an element2008 for shaping and steering the white light out of the wavelengthconverting element 2007. One or more sensors, Sensor1 2002, Sensor22002, up to SensorN 1904, are provided with the digital or analog outputof the sensor being received by the laser driver 2001 and a mechanismprovided whereby the laser driver output is modulated by the input fromthe sensors.

In a specific embodiment, the input to the laser driver is a digital oranalog signal provided by one or more sensors.

In a specific embodiment, the output from the sensors is measured orread by a microcontroller or other digital circuit which outputs adigital or analog signal which directs the modulation of the laserdriver output based on the input signal from the sensors.

In a specific embodiment, the input to the driver is a digital or analogsignal provided by a microcontroller or other digital circuit based oninput to the microcontroller or digital circuit from one or moresensors.

Optionally, sensors used in the smart-lighting system may includesensors measuring atmospheric and environmental conditions such aspressure sensors, thermocouples, thermistors, resistance thermometers,chronometers or real-time clocks, humidity sensor, ambient light meters,pH sensors, infra-red thermometers, dissolved oxygen meters,magnetometers and hall-effect sensors, colorimeters, soil moistersensors, and microphones among others.

Optionally, sensors used in the smart-lighting system may includesensors for measuring non-visible light and electromagnetic radiationsuch as UV light sensors, infra-red light sensors, infra-red cameras,infra-red motion detectors, RFID sensors, and infra-red proximitysensors among others.

Optionally, sensors used in the smart-lighting system may includesensors for measuring forces such as strain gages, load cells, forcesensitive resistors and piezoelectric transducers among others.

Optionally, sensors used in the smart-lighting system may includesensors for measuring aspects of living organisms such as fingerprintscanner, pulse oximeter, heart-rate monitors, electrocardiographysensors, electroencephalography sensors and electromyography sensorsamong others.

In an embodiment, the dynamic properties of the light source may beinitiated by the user of the apparatus. For example, the user mayactivate a switch, dial, joystick, or trigger to modify the light outputfrom a static to a dynamic mode, from one dynamic mode to a differentdynamic mode, or from one static mode to a different static mode.

In one example of the smart-lighting system, it includes a dynamic lightsource configured in a feedback loop with a sensor, for example, amotion sensor, being provided. The dynamic light source is configured toilluminate specific locations by steering the output of the white lightbeam in the direction of detected motion. In another example of adynamic light feature including a feedback loop with a sensor, anaccelerometer is provided. The accelerometer is configured to measurethe direction of motion of the light source. The system then steers theoutput beam towards the direction of motion. Such a system could be usedas, for example, a flashlight or hand-held spot-light. Of course, theseare merely examples of implementations of dynamic light sources withfeedback loops including sensors. There can be many otherimplementations of this invention concept that includes combiningdynamic light sources with sensors.

According to an embodiment, the present invention provides a dynamiclaser-based light source or light projection apparatus that is spatiallytunable. The apparatus includes a housing with an aperture to hold alight source having an input interface for receiving a signal toactivate the dynamic feature of the light source. Optionally, theapparatus can include a video or signal processing module. Additionally,the apparatus includes a laser source disposed in the housing with anaperture. The laser source includes one or more of a violet laser diodeor blue laser diode. The dynamic light source features output comprisedfrom the laser diode light spectrum and a phosphor emission excited bythe output beam of a laser diode. The violet or blue laser diode isfabricated on a polar, nonpolar, or semipolar oriented Ga-containingsubstrate. The apparatus can include mirror galvanometer or amicroelectromechanical system (MEMS) scanning mirror, or “flyingmirror”, configured to project the laser light or laser pumped phosphorwhite light to a specific location in the outside world. By rasteringthe laser beam using the MEMS mirror a pixel in two dimensions can beformed to create a pattern or image. The apparatus can also include anactuator for dynamically orienting the apparatus to project the laserlight or laser pumped phosphor white light to a specific location in theoutside world.

According to an embodiment, the present invention provides a dynamiclight source or “light-engine” that can function as a white light sourcefor general lighting applications with tunable colors. The light-engineconsists of three or more laser or SLED light sources. At least onelight source emits a spectrum with a center wavelength in the range of380-480 nm and acts as a blue light source. At least one light emits aspectrum with a center wavelength in the range of 480-550 nm and acts asa green light source. At least one light emits a spectrum with a centerwavelength in the range 600-670 nm and acts as a red light source. Eachlight source is individually addressable, such that they may be operatedindependently of one another and act as independent communicationchannels, or in the case of multiple emitters in the red, green or bluewavelength ranges the plurality of light sources in each range may beaddressed collectively, though the plurality of sources in each rangeare addressable independently of the sources in the other wavelengthranges. One or more of the light sources emitting in the blue range ofwavelengths illuminates a wavelength converting element which absorbspart of the pump light and reemits a broader spectrum of longerwavelength light. The light engine is configured such that both lightfrom the wavelength converting element and the plurality of lightsources are emitted from the light-engine. A laser or SLED driver moduleis provided which can dynamically control the light engine based oninput from an external source. For example, the laser driver modulegenerates a drive current, with the drive currents being adapted todrive one or more laser diodes, based on one or more signals.

Optionally, the quality of the light emitted by the white light sourcemay be adjusted based on input from one or more sensors. Qualities ofthe light that can be adjusted in response to a signal include but arenot limited to: the total luminous flux of the light source, therelative fraction of long and short wavelength blue light as controlledby adjusting relative intensities of more than one blue laser sourcescharacterized by different center wavelengths and the color point of thewhite light source by adjusting the relative intensities of red andgreen laser sources. Such dynamic adjustments of light quality mayimprove productivity and health of workers by matching light quality towork conditions.

Optionally, the quality of the white light emitted by the white lightsource is adjusted based on input from sensors detecting the number ofindividuals in a room. Such sensors may include motion sensors such asinfra-red motion sensors, microphones, video cameras, radio-frequencyidentification (RFID) receivers monitoring RFID enabled badges onindividuals, among others.

Optionally, the color point of the spectrum emitted by the light sourceis adjusted by dynamically adjusting the intensities of the blue “pump”laser sources relative to the intensities of the green and red sources.The relative proportions are controlled by input from sensors detectingradio frequency identification (RFID) badges worn by occupants of theroom such that room lighting color point and brightness levels match thepreferences of the occupants.

Optionally, the color point of the spectrum emitted by the white lightsource is adjusted by dynamically adjusting the intensities of the blue“pump” laser sources relative to the intensities of the green and redsources. The total luminous flux of the light source and the relativeproportions are controlled by input from a chronometer, temperaturesensor and ambient light sensor measuring to adjust the color point tomatch the apparent color of the sun during daylight hours and to adjustthe brightness of the light source to compensate for changes in ambientlight intensity during daylight hours. The ambient light sensor wouldeither be configured by its position or orientation to measure inputpredominantly from windows, or it would measure ambient light duringshort periods when the light source output is reduced or halted, withthe measurement period being too short for human eyes to notice.

Optionally, the color point of the spectrum emitted by the white lightsource is adjusted by dynamically adjusting the intensities of the blue“pump” laser sources relative to the intensities of the green and redsources. The total luminous flux of the light source and the relativeproportions are controlled by input from a chronometer, temperaturesensor and ambient light sensor measuring to adjust the color point tocompensate for deficiencies in the ambient environmental lighting. Forexample, the white light source may automatically adjust total luminousflux to compensate for a reduction in ambient light from the sun due tocloudy skies. In another example, the white light source may add anexcess of blue light to the emitted spectrum to compensate for reducedsunlight on cloudy days. The ambient light sensor would either beconfigured by its position or orientation to measure input predominantlyfrom windows, or it would measure ambient light during short periodswhen the light source output is reduced or halted, with the measurementperiod being too short for human eyes to notice.

In a specific embodiment, the white light source contains a plurality ofblue laser devices emitting spectra with different center wavelengthsspanning a range from 420 nm to 470 nm. For example, the source maycontain three blue laser devices emitting at approximately 420, 440 and460 nm. In another example, the source may contain five blue laserdevices emitting at approximately 420, 440, 450, 460 and 470 nm. Thetotal luminous flux of the light source and the relative fraction oflong and short wavelength blue light is controlled by input from achronometer and ambient light sensor such that the emitted white lightspectra contains a larger fraction of intermediate wavelength blue lightbetween 440 and 470 nm during the morning or during overcast days inorder to promote a healthy circadian rhythm and promote a productivework environment. The ambient light sensor would either be configured byits position or orientation to measure input predominantly from windows;or it would measure ambient light during short periods when the lightsource output is reduced or halted, with the measurement period beingtoo short for human eyes to notice.

Optionally, the white light source would be provided with a VLC-receiversuch that a plurality of such white light sources could form a VLC meshnetwork. Such a network would enable the white light sources tobroadcast measurements from various sensors. In an example, a VLCmesh-network comprised of VLC-enabled white light sources could monitorambient light conditions using photosensors and room occupancy usingmotion detectors throughout a workspace or building as well ascoordinate measurement of ambient light intensity such that adjacentlight sources do not interfere with these measurements. In an example,such fixtures could monitor local temperatures using temperature sensorssuch as RTDs and thermistors among others.

In an embodiment, the white light source is provided with a computercontrolled video camera. The white light source contains a plurality ofblue laser devices emitting spectra with different center wavelengthsspanning a range from 420 nm to 470 nm. For example, the white lightsource may contain three blue laser devices emitting at approximately420, 440 and 460 nm. In another example, the white light source maycontain five blue laser devices emitting at approximately 420, 440, 450,460 and 470 nm. The total luminous flux of the white light source andthe relative fraction of long and short wavelength blue light iscontrolled by input from facial recognition and machine learning basedalgorithms that are utilized by the computer control to determinequalities of individuals occupying the room. In an example, number ofoccupants is measured. In another example, occupants may be categorizedby type; for example by sex, size and color of clothing among otherdifferentiable physical features. In another example, mood and activitylevel of occupants may be quantified by the amount and types of motionof occupants.

FIG. 37B is a functional diagram for a dynamic, laser-basedsmart-lighting system according to some embodiments of the presentinvention. This diagram is merely an example, which should not undulylimit the scope of the claims. One of ordinary skill in the art wouldrecognize many variations, alternatives, and modifications. As shown,one or more laser devices 2106 are provided along with beam shapingoptical elements 2107. The laser devices 2106 and beam shaping opticalelements 2107 are configured such that the laser light is incident on awavelength converting element 2108 that absorbs part or all of the laserlight and emits a longer wavelength spectrum of light. Beam shaping andsteering elements 2110 are provided which collect light from thewavelength converting element 2008 along with remaining laser light anddirect it out of the light source. The light source is provided with alaser driver 2105 that provides controlled current and voltage to theone or more laser devices 2106. The output of the laser driver 2105 isdetermined by the digital or analog output of a microcontroller (orother digital or analog control circuit) 2101. The light source is alsoprovided with a steering element driver 2109 which controls the beamsteering optical element 2110. The output of the steering element driver2109 is determined by input from the control circuit. One or moresensors 2102, 2103 and 2104 are provided. A digital or analog output ofthe sensors is read by the microcontroller 2101 and then converted intoa predetermined change or modulation of the output from the controlcircuit to the laser driver 2105 and steering element driver 2109 suchthat the output of the light source is dynamically controlled by theoutput of the sensors.

In some embodiments, the beam steering optical elements include ascanning mirror. In an example, among the one or more laser devices, atleast one laser device emits a spectrum with a center wavelength in therange of 380-480 nm and acts as a violet or blue light source. The bluerange of wavelengths illuminates the wavelength converting element whichabsorbs part of the pump light and reemits a broader spectrum of longerwavelength light. Both light from the wavelength converting element andthe one or more laser devices are emitted as a white light. Optionally,a laser or SLED driver module is provided for dynamically controllingthe one or more laser devices based on input from an external source toform a dynamic light source. For example, the laser driver modulegenerates a drive current, with the drive currents being adapted todrive one or more laser diodes, based on one or more signals. Thedynamic light source has a scanning mirror and other optical elementsfor beam steering which collect the emitted white light spectrum, directthem towards the scanning mirror and either collimate or focus thelight. A scanning mirror driver is provided which can dynamicallycontrol the scanning mirror based on input from an external source. Forexample, the scanning mirror driver generates either a drive current ora drive voltage, with the drive current or drive voltage adapted todrive the scanning mirror to a specific orientation or through aspecific range of motion, based on one or more signals.

Applications for such an embodiment include any where there isaesthetic, informational or artistic value in the color point, positionor shape of a spot light being dynamically controlled based on the inputfrom one or more sensors. The primary advantage of the apparatus to suchapplications is that the apparatus may transition between severalconfigurations, with each configuration providing optimal lighting fordifferent possible contexts. Some example contexts that may requiredifferent quality of lighting include: general lighting, highlightingspecific objects in a room, spot lighting that follows a moving personor object, lighting that changes color point to match time of day orexterior or ambient lighting, among others.

As an example use case, the apparatus could be used as a light sourcefor illuminating works of art in a museum or art gallery. Motion sensorswould trigger the change in the shape and intensity of the emitted spotof light from a spatial and color configuration intended for generallighting to a configuration that highlights in an ascetically pleasingway the work of art corresponding to the triggering motion sensor. Sucha configuration would also be advantageous in stores, where theapparatus could provide general illumination until a triggering inputcauses it to preferentially illuminate one or more items for sale.

FIG. 38A shows a schematic representation of a use case for theembodiment described above. An object of interest 2504 is illuminated byan apparatus 2503 configured in accordance with the present invention.The apparatus provides a spot 2505 configured for general illuminationof the area containing the object of interest. A sensor 2501 isprovided, which is configured to determine if the observer 2502 is nearor looking at the object of interest based on the sensor input 2506. Itwould be obvious to one skilled in the art that the sensor can be of oneor more of a number of types. For example, the sensor could be aninfra-red motion detector or a detector based on measuring the occlusionof an infra-red or visible light beam. The sensor could also be acomputer vision system based on a video or still camera, which detectsthe presence of humans within its field of view. A computer vision basedsystem could also be used to determine if an observer's attention islikely to be applied to a particular object based on the tracking ofbody, head, facial and eye positions and motion.

FIG. 38B shows a schematic representation of the use case from FIG. 38Awhere the observer has approached the object of interest. The signal2507 measured by the sensor meets the predetermined criteria fortriggering a change in the output of the apparatus and the triggeringsignal 2508 is received by the apparatus. The trigger induces theapparatus to change the spatial distribution of the emitted white lightspot 2509 such that it accentuates the object of interest or otherwiseproduces the aesthetic conditions of the environment of the object suchthat it is more attractive and likely to be admired or purchased. To oneskilled in the art, it should be obvious that the sensor and apparatusmay interact in a number of ways, with either the sensor applying adigital or analog signal or communication to the apparatus or theapparatus requesting the status of the sensor using a digital or analogsignal or communication.

FIG. 38C shows a schematic representation of the use case from FIG. 38Awhere the observer has approached the object of interest. The signal2510 measured by the sensor meets the predetermined criteria fortriggering a change in the output of the apparatus and the triggeringsignal 2511 is received by the apparatus. The trigger induces theapparatus to change the spatial distribution of the color or spectrum ofthe emitted white light spot 2512 such that it accentuates the object ofinterest or otherwise produces the aesthetic conditions of theenvironment of the object such that it is more attractive and likely tobe admired or purchased. In this case, the apparatus changes the spatialcolor distribution to have a central spot of a different hue, but itshould be obvious that other changes to the spatial distribution arepossible. To one skilled in the art, it should be obvious that thesensor and apparatus may interact in a number of ways, with either thesensor applying a digital or analog signal or communication to theapparatus or the apparatus requesting the status of the sensor using adigital or analog signal or communication.

As another example use case, the apparatus might be used to illuminate alarge building such as an office space filled with cubicles, a warehouseor a factory floor, a retail location such as a grocery store ordepartment store, and the like. Motion sensors distributed throughoutthe space would detect motion and the apparatus would direct the lightspot towards the triggered sensors to provide local lighting for anymoving people. The advantage of such a system would be the ability toprovide lighting tailored to location and context within the space usinga minimal number of light sources.

Optionally, the beam steering optical element is a mirror galvanometeror could be a DLP chip, an LCOS chip, or a scanning fiver. Optionally,the beam steering optical elements are two or more mirror galvanometers.Optionally, the beam steering optical element is one or more MEMSscanning mirror with one or more axis of rotation. The MEMS mirror ispreferred due to the small size, shock resistance and cost. FIG. 34Bshows an example of a dynamic smart light source using MEMS scanningdevice as the beam steering optical element.

Optionally, the beam steering optical element is a polygonal scanningmirror driven by compressed air, stepper motors, servo-motors, abrushless DC motor or other source of rotational motion, though apreferred embodiment would use a stepper motor or other means of motionenabling open-loop control of the mirror position.

Optionally, the beam steering optical elements for dynamicallycontrolling the position of the white light spot will include one ormore lenses for collimating the white light or focusing the white lighton the scanning mirror. Optionally, the scanning mirror includes adiscrete component voice coil scanners or solenoids.

Applications include any need for triggered high speed data connectionssuch as oncoming traffic or pedestrians, presence of objects or people,changes to environment, dangerous or notable impending situations thatneed to be communicated. One example application would be as a lightingsource in buildings, where safety systems such as fire detection systemscould be used to trigger the apparatus to transmit evacuationinstructions and maps to the smart-devices [such as phones, tablets,media-players and the like] of occupants.

The apparatus would be advantageous in lighting applications where oneneeds to trigger transmission of information based on the input ofsensors. As an example application, one may utilize the apparatus as acar head-light. Measurements from a LIDAR or image recognition systemwould detect the presence of other vehicles in front of the car andtrigger the transmission of the cars location, heading and velocity tothe other vehicles via. VLC.

Applications include selective area VLC as to only transmit data tocertain locations within a space or to a certain object which isdetermined by sensors spatially selective WiFi/LiFi that can track therecipients location and continuously provide data. You could even dospace/time division multiplexing where convoluted data streams are sentto different users or objects sequentially through modulation of thebeam steering device. This could provide for very secure end user datalinks that could track user's location.

In an embodiment, the apparatus is provided with information about thelocation of a user based on input from sensors or other electronicsystems for determining the location of individuals in the field of theview of the apparatus. The sensors might be motion detectors, digitalcameras, ultrasonic range finders or even RF receivers that triangulatethe position of people by detecting radio frequency emissions from theirelectronics. The apparatus provides visible light communication throughthe dynamically controllable white light spot, while also being able tocontrol the size and location of the white light spot as well as rasterthe white light spot quickly enough to appear to form a wide spot ofconstant illumination. The determined location of a user with respect tothe apparatus can be used to localize the VLC data transmission intendedfor a specific user to only in the region of the field of view occupiedby the specific user. Such a configuration is advantageous because itprovides a beam steering mechanism for multiple VLC transmitters to beused in a room with reduced interference. For example, two conventionalLED-light bulb based VLC transmitters placed adjacent to one another ina room would produce a region of high interference in the region of theroom where the emitted power from both VLC transmitters incident on auser's VLC receiver is similar or equal. Such an embodiment isadvantageous in that when two such light sources are adjacent to oneanother the region containing VLC data transmission of the firstapparatus is more likely to overlap a region from the second apparatuswhere no VLC data is being transmitted. Since DC offsets in receivedoptical power are easy to filter out of VLC transmissions, this allowsmultiple VLC enabled light sources to be more closely packed while stillproviding high transmission rates to multiple users.

In some embodiments, the apparatus received information about where theuser is from RF receivers. For example, a user may receive data usingVLC but transmits it using a lower-bandwidth WiFi connection.Triangulation and beam-forming techniques can be used to pinpoint thelocation of the user within a room by analyzing the strength of theuser's WiFi transmission at multiple WiFi transmitter antennas.

In some embodiments, the user transmits data either by VLC or WiFi, andthe location of the user is determined by measuring the intensity of theVLC signal from the apparatus at the user and then transmitting thatdata back to the apparatus via WiFi or VLC from the user's VLC enableddevice. This allows the apparatus to scan the room with a VLCcommunication spot and the time when a user detects maximum VLC signalis correlated to the spot position to aim the VLC beam at the user.

In an embodiment, the apparatus is attached to radio-controlled orautonomous unmanned aircraft. The unmanned aircraft could be drones,i.e. small scale vehicles such as miniature helicopters, quad-copters orother multi-rotor or single-rotor vertical takeoff and landing craft,airplanes and the like that were not constructed to carry a pilot orother person. The unmanned aircraft could be full-scale aircraftretrofitted with radio-controls or autopilot systems. The unmannedaircraft could be a craft where lift is provided by buoyancy such asblimps, dirigibles, helium and hydrogen balloons and the like.

Addition of VLC enabled, laser-based dynamic white-light sources tounmanned aircraft is a highly advantageous configuration forapplications where targeted lighting must be provided to areas withlittle or no infrastructure. As an example embodiment, one or more ofthe apparatuses are provided on an unmanned aircraft. Power for theapparatuses is provided through one or more means such as internal powerfrom batteries, a generator, solar panels provided on the aircraft, windturbines provided on the aircraft and the like or external powerprovided by tethers including power lines. Data transmission to theaircraft can be provided either by a dedicated wireless connection tothe craft or via transmission lines contained within the tether. Such aconfiguration is advantageous for applications where lighting must beprovided in areas with little or no infrastructure and where thelighting needs to be directional and where the ability to modify thedirection of the lighting is important. The small size of the apparatus,combined with the ability of the apparatus to change the shape and sizeof the white light spot dynamically as well as the ability of theunmanned aircraft to alter its position either through remote control bya user or due to internal programming allow for one or more of theseaircraft to provide lighting as well as VLC communications to a locationwithout the need for installation of fixed infrastructure. Situationswhere this would be advantageous include but are not limited toconstruction and road-work sites, event sites where people will gatherat night, stadiums, coliseums, parking lots, etc. By combining a highlydirectional light source on an unmanned aircraft, fewer light sourcescan be used to provide illumination for larger areas with lessinfrastructure. Such an apparatus could be combined with infra-redimaging and image recognition algorithms, which allow the unmannedaircraft to identify pedestrians or moving vehicles and selectivelyilluminate them and provide general lighting as well as networkconnectivity via VLC in their vicinity.

FIG. 39A shows a schematic representation of a use case for one or moreapparatuses in accordance with an embodiment of the invention. Anunmanned drone vehicle 2201 is provided with one or more of the dynamicwhite light apparatuses 2205 along with a visible light communication(VLC) or radio-frequency receiver 2204. The apparatuses emit light spots2208 and 2206 that illuminate users on the ground. A terrestrial basestation 2202 transmits digital data to the drone using a radio frequencyor visible light communication channel 2203. This digital data isrelayed to the plurality of users via visible light communicationstreams 2207 and 2209 using modulation of the laser light in the whitelight beams 2206 and 2208. The VLC data is received by the user using asmart system such as a smart watch, smart phone, a computerized wearabledevice, a table computer, a laptop computer or the like. The drone 2201is able to change position vertically and horizontally to optimize itsability to illuminate and provide VLC communication to individualbeneath it. The drone can be a propeller driven craft such as ahelicopter or multiroter, it can be a lighter than air-craft such as ablimp or dirigible or it could be a fixed wing craft.

FIG. 39B shows a schematic representation of a use case for one or moreapparatuses in accordance with an embodiment of the invention. Anunmanned drone vehicle 2301 is provided with one or more of the dynamicwhite light apparatuses 2305. The apparatuses emit light spots 2308 and2306 that illuminate users on the ground. A terrestrial base station2302 is provided along with a tether 2303 that connects the base-stationto the drone. Digital data is transmitted to the drone through thetether along with electrical power for running the drone and providingpower for the white light emitting apparatuses. This digital data isrelayed to the plurality of users via visible light communicationstreams 2307 and 2309 using modulation of the laser light in the whitelight beams 2306 and 2308. The VLC data is received by the user using asmart system such as a smart watch, smart phone, a computerized wearabledevice, a table computer, a laptop computer or the like.

In some embodiments, the drone 2301 is able to change positionvertically and horizontally to optimize its ability to illuminate andprovide VLC communication to individual beneath it. The drone can be apropeller driven craft such as a helicopter or multiroter, it can be alighter than air-craft such as a blimp or dirigible or it could be afixed wing craft.

In other embodiments, the drone is not capable of independent control ofits position. In this case, the drone can be a propeller driven craftsuch as a helicopter, multirotor or the like. The drone can also be alighter than air-craft such as a blimp or dirigible or the like.

FIG. 39C and FIG. 39D show a schematic representation of a use case forapparatuses in accordance with an embodiment of the invention. In thiscase, two dirigible drones 2403 and 2407 are provided. In FIG. 39C, thefirst drone is provided with a base-station 2401 and tether. The seconddrone is provided with an independent base station 2408 and tether 2404.Each drone is provided with one or more of the VLC-capable, white lightemitters in accordance with an embodiment of this invention. A datastream 2402 is transmitted to a user via VLC communication 2405 usingmodulation of the laser component of a white light spot 2406 emitted bythe first drone. As the user moves, the drone provides continuousillumination of the user and VLC coverage to the user by a combinationof the drone actively altering its position relative to the user anddynamically controlling the shape and direction of the white light spot.In FIG. 39D, as the user continues to move they will eventually exceedthe range of coverage of the first drone, which is limited by the lengthof the tether and the throw distance of the apparatus. At this point, ahandover must be made to the second drone. The second drone 2411 nowprovides a white light spot 2412 for illumination as well as a VLC datastream 2415 provided from a second base station 2413 along a tether2414. It should be obvious to one knowledgeable in the art that morethan two drones can be used to provide coverage to an even larger area.Moreover, communication channels can be provided between base-stations,between drones or between remote control systems such that the locationsand motions of drones can be coordinated to provide superior coveragefor both illumination and data transmission.

In an embodiment, the apparatus is attached to an autonomous vehiclesuch as an autonomous car, truck, boat or ship.

In some preferred embodiments the smart light source is used in Internetof Things (IoT), wherein the laser based smart light is used tocommunicate with objects such as household appliances (i.e.,refrigerator, ovens, stove, etc), lighting, heating and cooling systems,electronics, furniture such as couches, chairs, tables, beds, dressers,etc., irrigation systems, security systems, audio systems, videosystems, etc. Clearly, the laser based smart lights can be configured tocommunicate with computers, smart phones, tablets, smart watches,augmented reality (AR) components, virtual reality (VR) components,games including game consoles, televisions, and any other electronicdevices.

In some embodiments, the apparatus is used for augmented realityapplications. One such application is as a light source that is able toprovide a dynamic light source that can interact with augmented realityglasses or headsets to provide more information about the environment ofthe user. For example, the apparatus may be able to communicate with theaugmented reality headset via visible light communication [LiFi] as wellas rapidly scan a spot of light or project a pattern of light ontoobjects in the room. This dynamically adjusted pattern or spot of lightwould be adjusted too quickly for the human eye to perceive as anindependent spot. The augmented reality head-set would contain camerasthat image the light pattern as they are projected onto objects andinfer information about the shape and positioning of objects in theroom. The augmented reality system would then be able to provide imagesfrom the system display that are designed to better integrate withobjects in the room and thus provide a more immersive experience for theuser.

For spatially dynamic embodiments, the laser light or the resultingwhite light must be dynamically aimed. A MEMS mirror is the smallest andmost versatile way to do this, but this text covers others such as DLPand LCOS that could be used. A rotating polygon mirror was common in thepast, but requires a large system with motors and multiple mirrors toscan in two or more directions. In general, the scanning mirror will becoated to produce a highly reflective surface. Coatings may includemetallic coatings such as silver, aluminum and gold among others. Silverand Aluminum are preferred metallic coatings due to their relativelyhigh reflectivity across a broad range of wavelengths. Coatings may alsoinclude dichroic coatings consisting of layers of differing refractiveindex. Such coatings can provide exceptionally high reflectivity acrossrelatively narrow wavelength ranges. By combining multiple dichroic filmstacks targeting several wavelength ranges a broad spectrum reflectivefilm can be formed. In some embodiments, both a dichroic film and ametal reflector are utilized. For example, an aluminum film may bedeposited first on a mirror surface and then overlaid with a dichroicfilm that is highly reflective in the range of 650-750 nm. Sincealuminum is less reflective at these wavelengths, the combined filmstack will produce a surface with relatively constant reflectivity forall wavelengths in the visible spectrum. In an example, a scanningmirror is coated with a silver film. The silver film is overlaid with adichroic film stack which is greater than 50% reflective in thewavelength range of 400-500 nm.

In some embodiments, the signal from one or more sensors is inputdirectly into the steering element driver, which is provided withcircuits that adapt sensor input signals into drive currents or voltagesfor the one or more scanning mirrors. In other embodiments, a computer,microcontroller, application specific integrated circuit (ASIC) or othercontrol circuit external to the steering element driver is provided andadapts sensor signals into control signals that direct the steeringelement driver in controlling the one or more scanning mirrors.

In some embodiments, the scanning mirror driver responds to input frommotion sensors such as a gyroscope or an accelerometer. In an exampleembodiment, the white light source acts as a spot-light, providing anarrowly diverging beam of white light. The scanning mirror driverresponds to input from one or more accelerometers by angling the beam oflight such that it leads the motion of the light source. In an example,the light source is used as a hand-held flash-light. As the flash-lightis swept in an arc the scanning mirror directs the output of the lightsource in a direction that is angled towards the direction of motion ofthe flash light. In an example embodiment, the white light source actsas a spot-light, providing a narrowly diverging beam of white light. Thescanning mirror driver responds to input from one or more accelerometersand gyroscopes by directing the beam such that it illuminates the samespot regardless of the position of the light source. An application forsuch a device would be self-aiming spot-lights on vehicles such ashelicopters or automobiles.

In an embodiment, the dynamic white light source could be used toprovide dynamic head-lights for automobiles. Shape, intensity, and colorpoint of the projected beam are modified depending on inputs fromvarious sensors in the vehicle. In an example, a speedometer is used todetermine the vehicle speed while in motion. Above a critical thresholdspeed, the headlamp projected beam brightness and shape are altered toemphasize illumination at distances that increase with increasing speed.In another example, sensors are used to detect the presence of streetsigns or pedestrians adjacent to the path of travel of the vehicle. Suchsensor may include: forward looking infra-red, infra-red cameras, CCDcameras, cameras, Light detection and ranging (LIDAR) systems, andultrasonic rangefinders among others.

In an example, sensors are used to detect the presence of front, rear orside windows on nearby vehicles. Shape, intensity, and color point ofthe projected beam are modified to reduce how much of the headlight beamshines on passengers and operators of other vehicles. Suchglare-reducing technology would be advantageous in night-timeapplications where compromises must be made between placement of lampson vehicles optimized for how well an area is illuminated and placementof the beam to improve safety of other drivers by reducing glare.

At present, the high and low beams are used with headlights and thedriver has to switch manually between them with all known disadvantages.The headlight horizontal swivel is used in some vehicles, but it iscurrently implemented with the mechanical rotation of the wholeassembly. Based on the dynamic light source disclosed in this invention,it is possible to move the beam gradually and automatically from thehigh beam to low beam based on simple sensor(s) sensitive to thedistance of the approaching vehicle, pedestrian, bicyclist or obstacle.The feedback from such sensors would move the beam automatically tomaintain the best visibility and at the same time prevent blinding ofthe driver going in the opposite direction. With 2D scanners and thesimple sensors, the scanned laser based headlights with horizontal andvertical scanning capability can be implemented.

Optionally, the distance to the incoming vehicles, obstacles, etc. orlevel of fog can be sensed by a number of ways. The sensors couldinclude the simple cameras, including infrared one for sensing in dark,optical distance sensors, simple radars, light scattering sensor, etc.The distance would provide the signal for the vertical beam positioning,thus resulting in the optimum beam height that provides best visibilityand does not blind drivers of the incoming vehicles.

In an alternative embodiment, the dynamic white light source could beused to provide dynamic lighting in restaurants based on machine vision.An infra-red or visible light camera is used to image a table withdiners. The number and positions or diners at the table are identifiedby a computer, microcontroller, ASIC or other computing device. Themicrocontroller then outputs coordinated signals to the laser driver andthe scanning mirror to achieve spatially localized lighting effects thatchange dynamically throughout the meal. By scanning the white light spotquickly enough the light would appear to the human eye to be a staticillumination. For example, the white light source might be provided withred and green lasers which can be used to modulate the color point ofthe white light illuminating individual diners to complement theirclothing color. The dynamic white light source could preferentiallyilluminate food dishes and drinks. The dynamic white light source couldbe provided with near-UV laser sources that could be used to highlightcertain objects at the table by via fluorescence by preferentiallyilluminating them with near-UV light. The white light source couldmeasure time of occupancy of the table as well as number of food itemson the table to tailor the lighting brightness and color point forindividual segments of the meal.

Such a white light source would also have applications in other venues.In another example use, the dynamic white light source could be used topreferentially illuminate people moving through darkened rooms such astheaters or warehouses.

In another alternative embodiment, the dynamic white light source couldbe used to illuminate work spaces. In an example, human machineinteraction may be aided in a factory by using dynamically changingspatial distributions of light as well as light color point to provideinformation cues to workers about their work environments and tasks. Forexample, dangerous pieces of equipment could be highlighted in a lightspot with a predetermined color point when workers approach. As anotherexample, emergency egress directions customized for individual occupantsbased on their locations could be projected onto the floor or othersurfaces of a building.

In other embodiments, individuals would be tracked using triangulationof RFID badges or triangulation of Wi-Fi transmissions or other meansthat could be included in devices such as cell phones, smart watches,laptop computers, or any type of device.

While the above is a frill description of the specific embodiments,various modifications, alternative constructions and equivalents may beused. As an example, the packaged device can include any combination ofelements described above, as well as outside of the presentspecification. Although the embodiments above have been described interms of a laser diode, the methods and device structures can also beapplied to other stimulated light emitting devices. Therefore, the abovedescription and illustrations should not be taken as limiting the scopeof the present invention which is defined by the appended claims.

What is claimed is:
 1. A LIDAR system comprising: a power source; aprocessor coupled to the power source and configured to supply power toa driver to generate a first driving current and a second drivingcurrent including modulation signals based on input data from anexternal source; a gallium and nitrogen containing laser diodeconfigured to be driven by the first driving current to emit a firstlight with a first peak wavelength; a sensing laser diode configured tobe driven by the second driving current to emit a second light with asecond peak wavelength configured to be a sensing light signal; awavelength conversion member configured to receive at least partiallythe first light to reemit a third light with a third peak wavelengththat is longer than the first peak wavelength, the third light beingcombined with at least partially the first light to yield a white lightand configured to pass, scatter, or reflect the second lightsubstantially without absorption; one or more optical elements coupledto the wavelength conversion member to receive the white light and tocollimate, steer, and project a first beam of the white light forilluminating one or more remote objects, and to receive the second lightto project a second beam of the sensing light signal centered with thesecond peak wavelength for mapping an area including the one or moreremote objects and their surroundings; and a detector configured todetect reflected signals of the sensing light signal for mapping the oneor more remote objects.
 2. The LIDAR system of claim 1, wherein thegallium and nitrogen containing laser diode is configured to generatethe first light with the first peak wavelength in violet or blue colorrange.
 3. The LIDAR system of claim 1, wherein the sensing laser diodecomprises an infrared laser diode for emitting the second light with thesecond peak wavelength in infrared range selected from one of 905nm,1000 nm, 1064nm, 1300nm, or 1550nm.
 4. The LIDAR system of claim 1,wherein the wavelength conversion member comprises a yellow phosphorconfigured to generate the third light with the third peak wavelength inyellow color range.
 5. The LIDAR system of claim 1, wherein thewavelength conversion member further comprises a blue phosphorconfigured to receive the second light and let the second light to passsubstantially without absorption.
 6. The LIDAR system of claim 1,wherein: the one or more optical elements comprises a first collimatorconfigured to collimate the white light to the first beam to less than15 degrees and a steering element for scanning the first beam ofillumination with a first pattern over at least part of the one or moreremote objects, the one or more optical elements comprises a secondcollimator to collimate the second light to the second beam of thesensing light signal to less than 1 or 2 degrees and comprises aprojector configured to project the second beam of the sensing lightsignal with a second pattern to the one or more remote objects and theirsurroundings, the second pattern being wider than the first pattern, andthe projector comprises one optical device selected from a MEMScontrolled scanner, a digital-light processing (DLP) chip, and a liquidcrystal on silicon (LCOS) chip for generating a mapping pattern with aplurality of pixels and dynamically scanning over the one or more remoteobjects to generate a 3D map thereof.
 7. The LIDAR system of claim 1,wherein: the processor comprises a first modulator configured to providea first modulation signal with a first rate to drive the gallium andnitrogen containing laser diode to emit the first light with the firstpeak wavelength which is interrupted with a second rate, wherein thesecond rate is substantially synchronized with a delayed modulation rateof the second light, the first modulator is configured to provide thefirst modulation signal based on input data from an external source foramplitude modulation of the first light with the first peak wavelengthin violet or blue range, the processor comprises a second modulatorconfigured to provide a second modulation signal to drive the sensinglaser diode to emit the second light with the second peak wavelength anddrive a transmitter component to transmit the sensing light signal withpulse modulation, and the second modulator is configured to provide asecond modulation signal based on feedback information from the detectorbased on reflected signals from the one or more remote objects withoptimal view angle and pattern for LIDAR sensing.
 8. The LIDAR system ofclaim 1, wherein: the detector comprises at least one selected from aphotodiode, a photoresistor, a CCD camera, an antenna, a scanning mirroror a microdisplay coupled to a photodiode to convert the reflected lightsignals to electrical signals, the electrical signals beingtime-dependent, and the detector further comprises a signal receiverconfigured to convert the electrical signals to an image of the one ormore remote objects and their surroundings, the image beingcharacterized substantially by the second peak wavelength and beingtime- dependent.
 9. A LIDAR system comprising: a power source; aprocessor coupled to the power source and configured to supply power toa driver to generate a first driving current and a second drivingcurrent including modulation signals based on input data from anexternal source; a gallium and nitrogen containing laser diodeconfigured to be driven by the first driving current to emit a firstlight with a first peak wavelength; a sensing laser diode configured tobe driven by the second driving current to emit a second light with asecond peak wavelength; a wavelength conversion member configured toreceive at least partially the first light to reemit a third light witha third peak wavelength that is longer than the first peak wavelength,the third light combined with at least partially the first lightyielding a white light, and configured to pass, scatter, and/or reflectthe second light substantially without absorption; a first set ofoptical elements coupled to the wavelength conversion member to receivethe white light and to collimate, steer, and project a first beam of thewhite light for illuminating one or more remote objects; a second set ofoptical elements configured to receive the second light and generate asensing light signal centered with the second peak wavelength andtransmit a second beam of the sensing light signal for scanning over anarea including the one or more remote objects and their surroundings;and a detector configured to detect reflected signals of the sensinglight signal for mapping the one or more remote objects.
 10. The LIDARsystem of claim 9, wherein the gallium and nitrogen containing laserdiode is configured to generate the first light with the first peakwavelength in violet or blue color range.
 11. The LIDAR system of claim9, wherein the sensing laser diode comprises an infrared laser diode foremitting the third light with the third peak wavelength in infraredrange selected from one of 905nm, 1000 nm, 1064nm, 1300nm, or 1550nm.12. The LIDAR system of claim 9, wherein: the wavelength conversionmember comprises a yellow phosphor configured to generate the thirdlight with the third peak wavelength in yellow color range, and thewavelength conversion member further comprises a blue phosphorconfigured to transmit the second light through substantially withoutabsorption.
 13. The LIDAR system of claim 9, wherein: the first set ofoptical elements comprises a first collimator to collimate the firstbeam of the white light to less than 15 degrees with a first pattern andcomprises a steering element for directing the first beam with the firstpattern to illuminate at least part of the one or more remote objects,and the second set of optical elements comprises a second collimatorconfigured to collimate the second light as the second beam of thesensing light signal to less than 1 or 2 degrees with a second patternand comprises a projector configured to project the second beam of thesensing light signal with the second pattern for mapping the one or moretarget objects and their surroundings, the second pattern being widerthan the first pattern.
 14. The LIDAR system of claim 13, wherein theprojector comprises one optical device selected from a MEMS controlledscanner, a digital-light processing (DLP) chip, and a liquid crystal onsilicon (LCOS) chip for generating a mapping pattern with a plurality ofpixels and dynamically scanning over the one or more remote objects togenerate a 3D map thereof.
 15. The LIDAR system of claim 9, wherein theprocessor comprises a first modulator configured to provide a firstmodulation signal with a first rate to drive the gallium and nitrogencontaining laser diode to emit the first light with the first peakwavelength which is interrupted with a second rate, wherein the secondrate is substantially synchronized with a delayed modulation rate of thesecond light.
 16. The LIDAR system of claim 15, wherein the firstmodulator is configured to provide the first modulation signal based oninput data from an external source for amplitude modulation of the firstlight with the first peak wavelength in violet or blue range.
 17. TheLIDAR system of claim 15, wherein: the processor comprises a secondmodulator configured to provide a second modulation signal to drive thesensing laser diode to emit the second light with the second peakwavelength and drive a transmitter component to transmit the sensinglight signal with amplitude modulation, and the second modulator isconfigured to provide a second modulation signal based on feedbackinformation from the detector based on reflected signals dynamicallyfrom the one or more remote objects.
 18. The LIDAR system of claim 9,wherein: the detector comprises at least one selected from a photodiode,a photoresistor, a CCD camera, an antenna, a scanning mirror or amicrodisplay coupled to a photodiode to convert the reflected lightsignals to electrical signals, the electrical signals beingtime-dependent, and the detector further comprises a signal receiverconfigured to convert the electrical signals to an image of the one ormore remote objects and their surroundings, the image beingcharacterized substantially by the second peak wavelength and beingtime- dependent.
 19. The LIDAR system of claim 1, wherein the first beamof the white light and the second beam of the sensing light signal arecombined in one beam.
 20. The LIDAR system of claim 1, wherein the firstbeam of the white light and the second beam of the sensing light signalare separate beams.